I just dug out my "set" of these.
Adam, I don't think he was asking if these were the 50's Canadian set. There were issued much later if in fact they are a legit issue. And supposedly they DID come out of Canada.
CNE stands for Canadian National Exhibition. See:
http://en.wikipedia.org/wiki/Canadia...nal_Exhibition
I have with the same stamped back: Aaron, Berra batting, Cash, Clemente, Kaline w/bats, Mantle Batting pose, Maris, and Mays as seen above.