Yes the 317 was contract made by Camillus for Buck. The 'Trailblazer' was made from 72 thru 1989. Found in two common versions. The first will have BUCK, Made In U.S.A., stamped on the tang and the second version will say BUCK, 317, U.S.A.. A couple of variations of the second will include special order issues by Smokey Mountain Knife Works with printing on the blades and a very few with a serrated secondary blade were also made. Prices remain firm on this big ole knife. Usually 50 to 100 depending on quality and version.
Yours looks to be in the 50 + range.
I have no idea why they are popular, one theory of my own is they look good with black motorcycle gear so maybe Harley guys like to wear them ?
The first knife with really small rivets in the scale was one of the first dozen made as
a salesman sample.