I have a few boxing exhibits as can be seen in my trade thread(link below). But I I have no idea why there appears to be 3 different color back grounds.There are some that are white,some that at are grey and then some that are sort of a green background. Does it have anything to do with different years? Or something that I had heard from another collector that the green backgrounds were issued in Canada. Any help would be appreciated. Thanks,
http://www.net54baseball.com/showthread.php?t=243517