The bottom is a Ringo not Paul and it doesn't look good to me (the R isn't shaped right, an extra hump after the I and not dotted correctly). None of the Paul's look right to me either....
I don't like the look of the "o" shape as a start. I compared this to a few of his lithograph signatures and other more recent examples I believe are authentic. It seems off to me. Further, it is perfectly placed, perfect and consistent ink adhesion and seems like it was not quickly signed. This could be from a different signing situation or from it being a forger. I wouldn't buy it.
I believe it is intended to look like the following but misses it.