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boxingcardmanI think, based on other cards I've seen, that on occasion ESCO made deals to print the backs of their cards with specific information for a business. In addition to the cookie cards mentioned already, I've seen ads for movie theaters on 1920s and 1930s exhibits and even an ad for a baseball card publication. I've also seen the cards with post-cutting ink stamps on the backs for advertisers, but these are readily distinguished from printings by their hand-placed look.
Given the size, complexity, uniformity and wet sheet transfer of the back printing you show I suspect that the publication made a deal with ESCO to do a run of ad cards for it. My guess is that there will ultimately be 32 (one sheet) or 64(two sheets) different cards.
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