I don't know for sure, but I'm going to say that the difference is the angle of the clear see-through area. Most of the Bledsoe Promo cards seem to have a diamond-shaped clear area, but only the PX1 has a rectangular see-through area. The regular insert set alters between both styles, so I think the Bledsoe Promos should do the same.
For those that commented about Beckett listings, Beckett actually says in the online set description that there were 2 Promos issued in packs, BUT they list 5 different cards AND the variation for FXP1. They list FX1a/b, FX2, FX3, FX4, FX5. There are scans of 3, 4, 5 also.
NO PWE's EVER!!! PLZ PM me 1st before sending any offer. ONLY selling cards as of March 2024. No trades or purchases right now.
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Largest total PC card collections by Team, then Athlete (as of 3/22/24):
STL Cardinals (MLB) - 8810; Carolina Panthers - 2888; GB Packers - 1790+ cards
Mark Martin (NASCAR) - 2038 cards; Jimmie Johnson (NASCAR) - 1875 cards; Jeff Gordon (NASCAR) - 1594; Ricky Rudd (NASCAR) - 839; Ozzie Smith (MLB) - 707