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!