Posted By:
MWJulie --
You are quite right that the originals have the subscription insert. But keep in mind that some subscribers or newsstand buyers probably pulled their inserts out and discarded them.
When I'm looking for original first issue SI's, I will only buy them if one of three situations exists: (1) they have the original mailing label, (2) they come with the original white mailing envelope, or (3) they have wear commensurate with a 1954 magazine.
As far as the 1954 baseball insert is concerned, they are, to the best of my knowledge, identical.