
Machine damage can be in one area/device or several in a row. One side or both side. It just how the machine/die move that damages the coins. Most of the time, coins are altered differently from strike to strike.

All these examples were from a couple of OBW rolls that all have the same marker on each coin.
Post 1990 coins have the mint marks as part of the design. So RPMs are impossible after 1989.
After 1990 if the mint mark is doubled and the rest of the surround devices are doubled, then it could be a doubled die. But I only know of one year that this happened.
