[BillyCoxDodgers3B]

This has nothing to do with the main question. Other people can chime in on that one.

Mantle index cards are pretty darn uncommon. Authentic examples that do exist tend to date to the earliest parts of his career, circa 1956 and prior. After that, demands on Mick's time due to stardom were such that he wasn't much bothered with answering fan mail, which is where the bulk of index card requests would have been coming from. By the 1970's, someone was applying a rubber stamp facsimile to index card mail requests, usually in bright red ink. By the time that memorabilia became more industry than hobby, next to nobody would spend money to have Mantle sign a worthless index card when they could buy a beautiful 8X10 at the show for a couple of dollars.

Honestly, I've barely seen any true index cards signed by Mantle which dated post-1950's. Most anything 3X5 in size that dates to later on in Mick's life was trimmed from a larger item, like a book leaf, and is obviously on thinner paper stock. If you see any actual index cards which supposedly bear Mantle's most familiar, "card show industry" style autograph, you're looking at an almost 100% chance of it being a forgery. I've seen lots of those.