Interesting info/research.
Thanks for your effort folks.
Beckett states there was a sealed set released that included the first 60 cards and a Laettner "Bonus Card" (non-auto).
One of the O'Neal autos (PR 2500) was available in a "hanging wall plaque' via Shop at Home.
No mention of how the others were distributed including the other O'Neal auto they have listed or the Jim Jackson.
Does the The National explanation make sense if there are a large number of these "unusual" backs out there, potentially both signed and unsigned? (I have no idea how these convention signings/giveaways work.)
Edit: After a bit more digging around PSA has graded a bunch of O'Neal unautographed "National cards". However, they are a mix of the image C2Cigars posted and the yellow uniform version that is listed here. I can't bring up any back images for them however. They also have graded Jim Jackson unsigned "National" cards but not any others.
Populations reports are here.