Doug - That's a really cool card. I'll agree with others that it's not rare but not something you see everyday. If you want one, and look hard enough, you will find one.
All 109 subjects in the 460 Series were overprinted with this back increasing the chances of some of the overprints not being lined up correctly with the sheet.
The Factory 649 OP's in the 150 Series had similar quality control issues at times. I don't have one that shows both factory numbers completely but I do have these two.
