Here is something maybe a little more odd. I got this in a lot of advertisements taken from what was described as Toy industry magazines. This one is called "Playthings". A quick ebay search only found 1 issue. Probably not something you could just buy off the news stand. Perhaps you had to be an industry insider to have access to the magazine?
https://www.ebay.com/itm/PLAYTHINGS-...gAAOSwMUpckZez
Avalon Hill did the Superstar Baseball game, which I used to play.
Makes me wonder if any of those 100 signed photos are out there and can they be linked back to the contest in any way?