This Camillus 53 on eBay is a great example of a knife that's as scarce as hen's teeth but because it's not known it lacks desirability so it's not valuable. I got my first one by accident. It was part of a lot of two on eBay. It has a long line tang stamp but no pattern stamp on the pile side of the main blade. My second one I paid a good bit more for but that's because of the individual I bought it from. It too came without a pattern stamp.
I researched the living dickens out of it but got no information, even from the old Camillus employees and only discovered the pattern number when I accidentally stumbled onto one online that did have the pattern stamp (I think it was on AAPK

). It's not in any of the Camillus catalogs I have available to me but considering the long line tang stamp I've come to believe it was made sometime in the very late '50s or very early '60s.

Today I stumbled on to this one currently on eBay which does have the pattern stamp ---►
https://www.ebay.com/itm/Vintage-Camill ... SwKLZcfvaw
This is only the 4th one I've ever seen. Draw your own conclusions.
Note the secondary blade has significant tang wear and has no snap.
Forged on the anvil of discipline.
The Few. The Proud.
Jerry D.
This country has become more about sub-groups than about it's unity as a nation.
"The #72 pattern has got to be pretty close to the perfect knife."
--T.J. Murphy 2012