No way.
It's a Mud Razor and the satin job is top notch.
I would be reluctant to let it go for $600.
The only time a quality mod will hurt the value of a Busse is if it is a super rare model, even then it should command almost as much as a safe queen.
Just look at a SHBM. A well done swedge or a satin job doesn't hurt the value at all. If I had a mint safe queen SHBM I wouldn't run out and grind a swedge on it but if I really wanted a swedge I would not hesitate.
yes, the finish is top notch.
a "fair" price, and top dollar are not the same. someone may be willing to spend 600.00 if it was listed.
a user mud razor probably would be fairly listed at what i suggested. though of course it could potentially sell for more.
ultimately it would depend on what one considers a modification.
a refinish could be a mod, but someone may not consider it so. a swedge is definitely a modification, and some may not mind that particular mod were they in the market for a particular model.
i would pay more for an "unmodded" blade, even a user, because no metal has been removed.
if i had a mud razor, and wanted it refinished as crafft has done, i would probably be willing to spend 100-125 for his work. but i wouldnt expect someone to pay the cost of the knife and the work were i to sell it.
maybe thats just how i see it.
i take nothing away from the time and effort needed to accomplish that finish.