Posted By:
dstudebaI really doubt they were stamped after they were trimmed. If you look at the printing on the trimmed sides it has been cut off by the trimming. I don't see a reason why someone would trim the cards down to a smaller size than the stamp prior to stamping it.
It is my belief that normal cards were stamped instead of an advertising display. Both of the overprinted cards shown have scrapbook residue on them so they could have been collected by the same person who trimmed them down before putting them in a scrapbook.