Hey Rob, the stamped back was required back in the day for tobacco products, most of the times it was printed but it could also be a stamp. So these ones have a factory stamp on the back.
Agree I have been buying from Joes for a while always great service, sends your graded cards out in a box. His auctions are more like ebay in that the fees are included in the price so if you bid and win at $50 you only pay $50. I have been very happy with the auctions, nice selection and fair prices it seems.