This appears to a real card from the 62 Jello set. It is trimmed far inside the borders which is why it may be smaller than it should be. The Jell-o advertising posters have Mantle in a batting pose with Yankee stadium in the background. The poster is large in red and white colors and does not have any facsimile card depicted on it.
Mantle is known to be on at least Apple Jell-o in 62.
I don't know if there was an advertising poster for the 1962 set. It was a test set purportedly released only in the midwest.
Here is a link to the 63 advertising panel.
https://www.google.com/search?q=1962...g-T_ldVnajM%3A