What I am seeing is apparently reflection from the lighting, giving the appearance of doubling. Take another pic of the coin at a different angle and see if it's still there or moves.
Yesterday, I noticed that Ken Potter had them available. I'm sure they are available other places. http://koinpro.tripod.com/books.htm
That's the 5th Edition, Volume II, and at $29.99 it's not bad. It covers half dimes to dollars. The question is do you want to wait for the 6th Edition for cents to nickels or do you want to get a copy of the 5th Edition, Volume I to match Volume II. You might check Whitman Books for the 5th Edition, Volume I if Potter doesn't have it. Chris
Does your coin look like this: http://www.ngccoin.com/coin-varieti...ollar-die-varieties/1942-ddr-50c-fs-801-3107/ I started this thread earlier today, might want to check it out: https://www.cointalk.com/threads/variety-photos.260626/