The first red flag is the super sharp corners. Those seem too good to be true. Any potential seller would be a complete idiot to NOT have that card graded first with corners like that (assuming it's a legit card).
Second, the colors on the face seem off to me. Compare to a real card and you might see it.
Third, the photos seem to be intentionally crappy, so it's hard to really tell for sure if it's real or fake. Notice how the case is so scratched up?
Fifth, and finally, the front and back photos seem to be two different cards. The front photo shows the card in a hard case and the background is dark, while the back photo has the card in a mylar sleeve with a white tile backdrop. This just seems like a scammer who's too lazy to hide the fact that these are two different cards.
We had a thread here just a couple weeks ago about a fake '51 Bowman Mantle, and one way to tell was from the printing on the back being just a little bit off (ie. where the copyright symbol lines up beneath the text above it).
Here's the previous threadL
http://www.net54baseball.com/showthread.php?t=239796