1968 O-Pee-Chee Mini-sized cards?
 

I have been looking for a 1968 O-Pee-Chee #37 Billy Williams for my collection for quite a while now and after finding 5-6 of them, have found that they are all about 1/16" short top to bottom and do not appear to be trimmed. After checking the PSA pop report I see only 3 examples of this card have gotten # grades and 2 graded A. Just want to pick the brains of some more experienced collectors and find out if size from the factory is a common problem with this card?

Thanks for your help and any information would be appreciated.