Thanks for replying and the links to research. It was helpful.Yes, the round shiny silver Signature Rookies hologram circle is on the back of the card. Apparently the "T" cards (38 of them) were part of a random parallel insert set within the 1995 Signature Rookies Preview set which consisted of about 80 cards or so. The #12 Billy Hall and the #T12 Billy Hall apparently are two totally different pictures of him on each of the cards. I still don't know why the "T" cards are # /5000 instead of # /6000 ?