Posted By:
Leslie WestbrookI'm not sure how much of a premium would be placed on that card specifically, but I can tell you what I paid for two of my wrong back cards. I bought a 1941 Play Ball Joe Cronin (probably would grade about a 5-6) with a an upside-down Ralston Helmsly back for about $30 on Ebay. That was the only example of that card that I'd ever seen. Also, I picked up a 1974 Steve Garvey in NM-MT condition with a Milt Pappas back for $10. It didn't seem that in either case much of a premium was placed on the card. In fact, it seemed that the Cronin may have sold for more with the correct back.
All that said, there are a lot of Mantle collectors out there (including me) who might be interested in the card because it's different. I sent you an email also, but if you ever think you might want to trade or sell yours (if that one's yours), then I'd be interested.