Dan,
This is the Trailblazer, a contract knife made for Buck by Camillus from approximately 1970 through 1990. I do not know this for certain, but I suspect shipments from Camillus may have ceased sometime prior to that and it took until about 1990 to deplete the inventory to the level that the 317 was removed from the Buck catalog. I think the knife was always 440C.
You will often find one, or more, on eBay, sometimes even in new-in-box condition with sheath. The earliest models had the MADE IN U.S.A. tang stamp with the model number on the reverse side. Then, about 1971 - 1972, the tang stamp was changed to the three liner - BUCK / 317 / U.S.A.
Hope this helps and that I have not told you more than you cared to know!
Larry
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"He is no fool who gives what he cannot keep to gain that which he cannot lose".