1970s Sports Illustrated Poster Cards. Info please!

[JackieMoon]

Is anybody familiar with the old Sports Illustrated "poster cards"? I've asked a few places and nobody seems to know much. The cards are on heavy card stock with blank backs and measure 3" by 4 1/2". My best guess is they were used by dealers/retailers to sell the larger posters (similar to the 1980s-90s Nike poster cards except much older). Beckett has graded a small amount of these as "1970-73 Sports Illustrated Poster Cards," but no basketball players only some football players plus tennis player Arthur Ashe (there is one for sale on ebay right now).

I'm curious how many players were featured, how rare these are, etc, particularly the basketball players. I have a Jerry West, Walt Frazier, and Spencer Haywood (see pics), and I've seen evidence of a Connie Hawkins, Nate Thurmond, and Willis Reed as well, but that's it.

Any info appreciated. Thanks!

[JackieMoon]

One-time bump in case people missed it. Having trouble getting any info on these cards.

[Exhibitman]

I think they were display pieces for point of sale displays. As I recall, the SI posters were sold from a retail display that had the cards arrayed on a board above a cubby of rolled posters. You could see the poster from the card and then pull a rolled poster from the cubby and buy it. The #s corresponded with the cubby hole.

[JackieMoon]

Thank you, Exhibitman. I figured it was something like that.

[Justus]

I have several football cards and have also always wanted more info.

[JackieMoon]

So I found a few more. Can't get enough of these I love 'em. Still hoping for more info, but given how rare and under the radar they seem to be I'm starting to doubt there is much info available other than what's already been said in this thread. Anybody ever seen that "Pro Basketball" poster in the wild? I've seen all the others but not that one.