1951 Bowman Cloyd Boyer with Billy Goodman back overprint. What happened here is easy enough to figure out: the front was printed and the sheet was put into the press wrong side up and inverted for the back printing, so it got printed twice on the front and not at all on the back. Now, whether that was on purpose because the front was misaligned and they decided to use the sheet to clear the press I don't know. Still fun to have for my printing freaks collection.