A friend recently gave me a lightly used Camillus 707 Copperhead as a payment for debt. It looks the same as the one here http://www.theknifeauction.com/item.php?id=55988 except it has no blade etching or serrations. The tang of the main blade is stamped CAMILLUS NEW YORK U.S.A. in the most recently used style on one side and 707 on the other. The other blade is stamped PATENTED. Anyone know anything about this knife such as value, etc?