The date of manufacture of Remingtons can be determined from a 2 or 3 letter code on the left side of the barrel just ahead of the receiver. The key can be found on the Remington web site, as well many of us have it and can interpret it for you.
Your rifle was manufactured in February of either 1954 or 1980. 1980 was the last year of manufacture of the 760 (before the 7600 and other designations).
If the rifle is of the old style with vertical slits cut into the forestock, and a "rounded" configuration it's a '54. If the forearm has checkering pressed into it and has a more modern appearance - similar to the 7600 - then it's a 1980.
Is your 760 a Carbine 18.5" barrel? I have a 308 CARBINE .
I bought it up in Orillia. I paid 425.00 plus taxes. The wood had a few dings but the blueing was mint. I have since bought another 760 AS NEW on CGN 30-06 22" pipe. I exchanged the wood, now my 308 Carbine would rate "MINT". I have not hunted with it yet. I want to scope it first with a Luepold VXIII 1.5-5x20. If your gun is in excellent condition you will have no problem getting 425.00 - 450.00 for it. If it is a Carbine model then I can see you getting 500.00 - 550.00 The Carbines are getting harder to find.