I think you are going to find that it is just due to the terrible picture, its all fuzzy. The thread Chingford mentions is probably this one but it deals with William IIII pennies, in particular the 1834. 1834 Penny Missing Serifs I spotted the REX from a dealers gallery picture which wasn't enlarged, i've only enlarged here because it was only 22kb, so it's not my imagination. The 2 serifs at the bottom of the X have a curve going up towards the leg of the X, the E has something poking out from the vertical leg of the E and the R looks over an R. I know sometimes pictures can play tricks on you, but with 3 different letters, and only of the REX, why not the rest of them to? As i said, i spotted this from a 22kb dealers gallery picture.