Pj,
There are several reasons Bucks could have ground off the tangs. Various methods have been used to show a factory second. Lately, grinding tangs has not been one of them. Buck has sold seconds. Buck has also built knives from leftover parts for primitive country missionaries to have to give out.
These come in all kinds of wild configrations but generally have a deep ground groove in one bolster. If you see these for sale please tell Buck.
The barlows were Camillus made, I saw ground off tangs and unground-off tangs come from the closing of the Camillus factory from several different models. The big 2000 blade marked trapper comes to mind. A batch came out with no ink blade stamping, some with markly different side to side bone scales (the original seconds) and brass rivets insead of SS. I also have a 303 with the tang ground off and Remington is pad printed on the tang. I think your GDaddy Barlow is a Camillus cloesdown special, notice the escutcheon is ground or not printed also..
When the factory closed there were auctions for every piece of equipment and supply, people went and bid on large bins of "stuff' some lots were of these 'close-out specials". that is why you saw and continuce to see some on 'majorauctionsite'. I will go out on the ole limb and say your particular one is a Camillus second that eventually got sold at closing or sold by SMKWs in some deal.
I am not a lawyer, but I would guess Camillus owns all parts not used in full-filling the Buck contract. If legal obligations allowed and no future cooperation was hoped for, then it was everyman for themselves......If I was Buck and had been friends with Camillus, I might say 'just grind off the tang' but you can leave the bolster.' Who knows. Its still an interesting piece for your knife shelf.
Has your question been addressed. 300Bucks