That "cannoli" line was spoken by Richard Castellano, not Al Pacino. Well, who authenticated the other book that was sold at the charity auction? It seems incredibly legible for a Pacino signature - secretarial? Not sure - haven't seen enough apart from his abbreviated "signatures".
Both the book and the customs form have been signed by Pacino's secretary. Like Richard said, everything mailed to him is signed by the same person.
He has done a few actual signings for payment and can indeed sign a semi-decent autograph now and again, but the majority of Al's autographs are just checkmarks.
The following are in-person street signatures...
and last are the modern for friends & paid signings