Help with Authenticity - Ruth, Mantle, Mays

[redauto5]

Hey Net54! I'm new to these parts, spend most of my baseball card forum time over at Blowout. I have an opportunity to purchase a pretty sweet collection. A large part of the value consists of a few cards I would really appreciate the expert opinions of this forum on regarding authenticity. I know the pictures included may not be extremely helpful, and I have the opportunity to get better pics but this is what I have currently. The cards I'm curious about are:

-1933 Goudey Sport Kings Babe Ruth
-1952 Topps Mays Rc
-1953 Mantle
-1956 Mantle

The seller has an SGC graded 1933 Goudey Gerhig, a nice BGS graded Gretzky RC and some other nice graded vintage cards so its plausible the above 4 cards are all authentic. I question the Sport Kings Ruth the most as I think that's the easiest to fake. FYI the seller has had this collection since the 90's and I'm confident he purchased all of them assuming they were authentic.

Thanks in advance for any guidance ya'll can give! I'm obviously super excited about the collection and the opportunity to own such iconic cards but I want to be as informed as I can and tread carefully.

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