[perezfan]

They're from the late 40s / early 50s. Here are some other variations....

http://www.ebay.com/itm/1950s-Pittsb...01753080743973

http://www.ebay.com/itm/1940s-Boston...-/160671946267

http://www.ebay.com/itm/1950s-Clevel...41158328933524

http://huntauctions.com/phone/imagev...3&lot_num=1086

I believe Mike's Tigers example to be among the toughest, with Indians being the most common.