It doesn't look like an original seal.
In photos 2 & 3, there's a seal seam across the bottom . The seam was generally flush with the cover seam.
In photo 1, you can see in the upper right corner that the shrink is a little looser and wrinkled; also to a lesser degree in the lower left corner. I think it should be tight.
Can't really tell from the photos the legitimacy of the cover itself. Still, the back cover doesn't look 60s, but it's hard to really say from the photo.