The 6.5" barrel ended in 1979, the "-3" came out in '82, the "-4" in '88 so it has to be a 6" gun & even in nice shape without the box & docs for me $650 is top dollar, but again a lot has to do with how popular these are in your area and of course how badly you want it. If you intend to keep it & are happy with it then I'd say go for it. Start low, you can always go up. Good luck, hope you make a deal you're happy with & as we love pics make sure you put some up when/if you get it.