I wouldn't put the 80's models as newer if it was me.

Older models seem to have the following

Much nicer grades of stocks
Deeper blueing with less machining or brush markes
Great triggers out of the box
metal floorplate and trigger guard
All are extremely pressure bedded (too much IMO)

Newer ones have the obvious faults, but seem to be bepressure bedded from the factory at one point in the forarm unlike the older ones and not near as tight. One of my new ones had its crown out of round. Another one had excessive throat lengths. And all had horrible triggers.