I asked this in Levine's forum several years ago and he suggested late 50s, made in either in the US or Japan for import and typically sold cheaply in Army/Navy and discount stores. My grandfather geared up for camping with his boys in the 50s with lots of surplus stuff, so that's consistent.
Here's a better shot.
Grandpas Knife by
Pinnah, on Flickr
My granddad got me into hunting and when he was too old to walk in the woods, gave me his Winchester and 30's vintage Johnson Woolens hunting jacket. A year or so after he passed (and his sister had passed), I got into the old fallow family homestead, found and took the knife. I didn't bother asking anybody for permission. Sort of figured it was my job to keep the set together. Lousy shot of the knife, but you get the idea...
grandpas-stuff by
Pinnah, on Flickr
EDITED TO ADD: this knife is now a "safe queen", but I trust you can understand why. Worthless on the collectors market. Priceless to me.
This helps and if this is the case, then my H-15 + Silkyboy Saw are my "big knife" by which I mean the stuff I carry if I'm going to be processing wood. Mostly this only for winter ski tours but occasionally on low mileage trips and always with the Emberlit stove. The H-15 (or Mora, which is a bit over 4") have plenty of splitting power for the stove I burn in the Emberlit.
My "small" knife then, would my Squirt, which I know isn't very romantic and all that but when I have to sew gear in the field, the pliers become very useful for driving a needle through heavy webbing and nylon.
FWIW, my Opinel has about a 3.5" blade (about the size of my Buck 110) and the joint is robust enough to batton up to 2" wood with so long as the lock ring is NOT engaged so the joint is free hinging. Obviously it's not something one would want to do all the time with that knife but it can be done if you work with care and there's no other folding knife I would attempt that with (except a Svord Peasant, which I've not yet tried). I try to keep pack width as low as possible so I'll carry either the H-15 or the Opinel, but not both.