I'll give my 2 cents worth if it is even worth that, But I would look at the barrel first and see how it looks, must of them should be dark, like mine I just got, but still has good rifling. Second would be check the numbers on the bolt, reciever to make sure they match up (not elecrostencilled), then on magazine and butt plate. If you are into how comman that particular year and manufacturer, this is a website that will tell you, you might find a rare one if lucky. But like I said, I am still new and have been a lot of reading myself. Hope this helps.