It's been quite a while since we had any input on this thread. I was checking out the latest auction for Hake's Americana today and came across a pin-back which would match the earliest baseball collectible for Denny Matthews, Frick Award Winner from the KC Royals and a HOF inductee from 2007. Here is a link to the item in case anyone is interested:
https://www.hakes.com/Auction/ItemDe...ATTHEWS-BUTTON