As a preface, I'd like to say I am neither Filipino, or from the Philippines.., so those who are "experts" on the culture and/or very familiar with Batangas Province, be gentle!

I have however been there twice, so I'd like to add "food for thought" for whatever it's worth.
Firstly.., out of thousands of Balis I saw while visiting, I never saw a "maker name" on a Batangas style Balisong.., although I believe some families may have a file marking that indicates their work. I have seen a few with a name or logo of some sort.., but these WERE NOT Batangas Balisongs..., and though some of them may have been produced in Olangapo, I understood that they were primarily made in Manila (a different animal so-to-speak).
I am 99% sure the Balisong on the auction that "RGRAY" asked about was built by a gentleman named Noel Medina Lanusa, who resides in "Buli" (Taal, Batangas Province) Though I can't vouch for the claim that he has made them for 35 years (as the add says), he is not a "Spring Chicken".., and to the best of my knowledge, the "finish" on his Balisongs is now mostly done by a man named Danny Chua, who also lives in the Philippines, but I don't know where exactly. I lost his email address

...but I think "Batangueno" knows Dan, so maybe he could chip in with more information if possible?
RGRAY's question was about "worth", so I just wanted to add my own perspective. I do have several Balis made by Noel (among other makers).., and have "flipped" them extensively. Like any FHM I've ever had, they do require "loosening up" (i.e., the process Clay describes on his site), rocking a wide-blade screwdriver in the blade-well to sort of ease the tightness of the pins. Mine work really well, are scary sharp.., and the stag inlays are gorgeous and well-pinned. Given the fact that Filipino craftsman use nails and/or thin stainless rods for the pins (if they can get 'em).., I don't know how long they will hold up if used constantly for manipulations. Mine are nice enough that re-pinning them wouldn't bother me a bit though.
The value of these pieces (to me).., is basically very simple. They represent what I think may be the last of a quickly fading "Cottage Industry" that gave birth to our hobby and love for these knives. The younger folks in Batangas, who would typically evolve from "helper", to "apprentice", to "journeyman" Balisong makers, seem to have less interest in carrying on the traditon, and leave to find more lucrative employment possibilites in the major cities.
My two visits (which span 30 years), made this very clear! In the middle 60's, the roadside vendors with these knives were literally everywhere in our fabled "Barrio Balisong" marketplace. This is not the case now, with vendors scattered sparsely among artisans that make woven bags, picture frames, etc. I was told (by many), that although there were "some" makers that live in Balisong, that the vast majority of these pieces were, and are now, make in Taal (which isn't far). Barrio Balisong is basically a "Market Place" for lack of a better or appropriate term.., and during my last visit, it was interesting to see that all those selling these knives were "older folks".., definitely not the case when I first visited.., and in my opinion, further proof of the decline of this Batangas style cutlery as a viable way of survival in a poor economy.
I have been lucky enough to see a few "family makers" at their craft (although not Mr. Lanusa).., and most of the blades I saw being crafted were fired and cut from what the locals called "race"...the caps of the housing that enclose the bearings on trucks (52100 I think). I also saw some made from truck spring materials (and don't know if the term "race" applies to this also) <~~ need help on this Batangueno/Armand/et.al.

The closest thing I ever saw to a "Power Tool".., were a few grinding wheels with sort of generator set-ups that could be in the Smithsonian Institute.., and some that were powered by a family member peddling a bike <~~ REALLY! Other than that.., large retangular blocks used like an "Anvil" ~~> for pounding sheets of brass, ball-peen hammers, bastard files, small hand files, an open coal-burning stove for forging, oil buckets and tongs for dipping, red and green rouge called "SEBO" (I think)?..., and wads of T-Shirts they use to do hand polishing with the rouges -no Baldor Buffers-!! The sharpening stones I saw (only two), may have been carborundum, but not for sure? The only thing I can say in Tagalog is "I love you", so I passed on questions in most cases.
In fact.., 80-90% of the Balisongs I saw for sale were only sharpened for 1/2-3/4" from the blade-tip. Afterall, this knife was designed with the intent to puncture/stab.., and not for peeling veggies! The vendors I saw would sharpen the full length of the blade for what would be about $.50 in our exchange, but I really can't remember seeing many roadside vendors with fully sharpened blades unless someone ordered it that way.
As you all have seen countless times on various FHM's.., the insert materials (especially "bone") vary widely.., and I did see makers etching and coloring the striations on many inserts (i.e., enhancing the looks artificially).
Again.., someone jump in here, but the stag on those handles posted on BA.., are NICE, with natural curvature, and I believe they are probably from Mindoro, in the Mindanao area (south of the Philippines)where Abu Sayyaf is currently ruining everyone's day. My current understanding is that wild mountain deer indigenous to the Philippines ("Usa").., are highly protected and not hunted except illegally. There are also "cultured deer" raised on farmlands by those more wealthy, and perhaps some of the antler material can be harvested by Batangas folks?? I don't think they could afford it.., again if anyone knows I'd be interested. As with most "animal horn", I believe it is also safe to assume the darkened striations even on this REALLY NICE STAG may be enhanced to some extent with dyes, and that a chemical process of some sort is used to prevent shrinkage, deterioration, etc.
Sooooo..., what is it worth? Hmmmmm.., in my opinion it is worth whatever having a true piece of the history of this "hobby" is worth to the individual. The pieces I have are far and away superior to WWII models I have; in form, function, and balance.., and I'd trade (5) Jags for that one on BA (if I already didn't have a few). They are a strong knife given what I've mentioned above. They are not a representation of Bali-Song Cutlery, Pacific Cutlery Corp., or Benchmade, nor a Dobruski, Erickson, Ralph, Monarch, Tachyon, etc., and although the temptation to "compare" is real, and also valid if you only want one or two Balisongs, it is pretty amazing for me to fool around with mine.., giving thought to "the process" by which they became a Balisong!
The artisans that produce these knives are exremely proud of their work.., and will be happy to ram the blade-tip of their knives through a Peso to demonstrate their quality. <~~ Not a recommendation, I've never done it.., but have seen it done more than once with pieces similar to the one pictured on Blade Auction. They smile and show you it didn't hurt the knife, then raise the price.

(that was a joke)
Conclusion: (Length of post??? <~~ I blame the Holdiay)
- The knives range in quality from "not-so-hot", to REALLY NICE!
- They are a truly HANDMADE piece of art.
- Their value is dependent upon the individual buyer/user.
- The availablity of REALLY NICE pieces will probably die out.
- Stag insert pieces will DEFINITELY become scarce...soon!
- If quality Batangas makers vanish, then what's the value?
- I like 'em, and enjoy owning knives made in this fashion.
Please feel free to add-to, subtract, divide or conquer anything I've said here!! I actually wish I'd had the foresight to travel with someone that spoke Tagalog, and/or had "local knowledge". Between trips I found very little difference whatsoever in the way knives were made, but sadly..., far fewer makers.
Hope everyone had a restful, safe holiday!
"Hunters seek what they [WANT].., Seekers hunt what they [NEED]"