your gun shows ILS keys in the pic, so it is unlikely to be a 1974 gun.
that is something fairly recent. like 94 and up or 2000 and up, can't remember.
it appears to be a stainless gi model, so the grips are wrong as well.
but can't see the sights to be sure.
could be a mil spec.
eitherway someone replace the grips.
NM or N on the serial number makes a difference to some buyers.
NM designates assembled in the US vs N built in brazil.
New ones seem to run around 700 right now. if they are still being sought after, you could easliy get new prices assuming in good shape. hard to tell from the picture. if it has idiot scratch or any other issues.
but again, depends on how much someone wants it right now.