I humbly offer this anomaly that I've been chasing (seemingly alone) in the light of what are, to me, much more important issues (like the N2 lithographs).
This set contains three variations, all featured on the backs. There is the black type on white back (the most common), blue type on white back and the blue type on gray back (least common).
There are 36 cards in the set; all the "stars" are basically B movie players, supposedly selected by Photoplay Magazine. Photoplay also sponsers the promotion on the backs that feature 6 different send-away products. They are numbered 601 thru 606 and the numbering coincides with the numeric grouping of cards - in other words, cards
1 thru 6 have promotion 601 thru 606 and then the pattern starts over again with cards 7 thru 12 having promotions 601 thru 606 - this is repeated 6 times for a total of 36 cards; 6 promotions, each on 6 different cards.
This set is one of the few pre-1950 movie star sets issued in the States. This set, along with the 1936 Golden Grain, 1932 Shelby Gum, pretty much represents the sum total of gum cards widely issue in the US to feature movie stars. I know there are other gum card sets; I'd be interested in hearing from fellow collectors who know something about the other prewar gum issues of movie stars.