Quote Originally Posted by mpd1978 View Post
Look at the proof mark for signs of a 'through the finish' punch mark, also you can look at the rear sight dovetail staking for bare metal in the staking. Not always seen unless the carbine is in pretty good shape though.

Attachment 14454
Not to derail my own OP, but there seems to be a lot of contradictory info about the presence or absence and shape (chisel, punch) of stake marks on the dovetail rear sight mount on the receiver regarding the USGI flip sights. If there are no pronounced marks, does that mean that an adjustable ramp sight was never mounted per arsenal rebuild?