Hi, I recently won a 15OT on ebay. I was wondering about it's approximate age. The markings on the knife read "Schrade-Walden, New York U.S.A " and on the other side it says "15OT patent pending" It came with a basket weave type sheath with a leather thong threaded around the edges of the sheath. It is in pretty good condition with no rust but a few spots of minor pitting.Only paid $33 + shipping. Any info would be appreciated. Thanks in advance.