I started collecting in the early 70's. Fortunately, I've kept most of what I wanted to keep.
Contrary to popular belief, there where good knives made way back when, Buck, Kershaw and at the time the cream of the crop, IMO, Gerber. They aren't even a shadow of their former selves, but they used 440C, very well heat treated in their early folders (when 440C was what quite a few custom makers used), L6 in there survival knives (VERY tough steel) and M2 in there Armorhide hunters. Unless one was in the tool and die industry or metallergy, most folks didn't know what M2 was.
A couple that I wish I had kept were an original Paul knife, and a Mark I and Mark II from Gerber.
Q