The RPM is known, and I believe that may be the top of another 7 down there in the denticals. I think you can also see part of an 8 in the denticals under the left side of the 8. I suspect the lines are heavy hairlines on both side of the coins. Tap the edge of the holder so the coin shifts in the 2X2 and see if the lines stay in the same place on the coins. If they do then they are hairlines.

























