A number of cards in this set have been cut with a black horizontal line at the top and others have a white horizontal line at the top. Some can also be found with the line at the bottom. A few can be found with either the black or white line, such as #97 Joe Moeller--I have both the black line and the white line version.
Regarding the OP's #463 Frank Robinson AS card, there is a black line version presently viewable on COMC's site and I'm sure there others out there. fwiw, I'm confident the OP's card is not fake.
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