First, I think you're applying "wire photo" in too general a sense. "Wire photos" are photographs that were actually transmitted "over the wire" meaning through the phone lines (picture a higher-quality fax machine for photographs). What they have there is not a wire photo. You could call it a press photo or a news photo, but it was developed from the negative, not sent over the wire.
The Acme stamping on the back is consistent with their last stamping style which would have been used in 1951, as the paper caption is dated. They were acquired by United Press in 1952, so no more Acme stamping after that. There is also the big red SPORT stamp which indicates that the photo came from the archives of Sport Magazine whose photo archives were broken up and sold off a couple of years ago. It's not uncommon to see photos from their archives floating around, and I have a number in my own "to be sold" stack.
So everything looks on the up and up to me, and I would feel comfortable identifying this one as a Type 1 original photo from the period dated on the caption.
As for the seller, I've bought from them a few times and had no complaints (other than that they are in TN also, so I always have to pay sales tax
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