I can add my .02¢ on this SpaceJam jersey topic. I'm 40, and vividly remember when JC Penney sold high end Nike & Jordans and Authentic jerseys (all sports). When the movie released, they had the Space Jam jerseys. They WERE made by Champion. I remember them going on clearance (my best friend worked there and we would look through the sports stuff and shoes all the time when I stopped by). I never picked up the jersey (but I should have since it was CHEAP).
They were made by Champion as they still had the NBA contract for the 95/96 season (I also remember buying the Bulls Authentic pinstripe Jersey @ Champs when they released as I worked at Foot Quarters way back then & got 30% off it). But Champion did make them originally.