The question is how much of it is directly taken from the Puzo script, and how much is artistic license. Maybe Puzo changed certain elements from his original novel himself.
Agreed. I guess we'll never know. I know Puzo placed discrepancies between his book and the movies (Vincents existence for example), which bothered me also. Too many contradictions in this last installment make the whole body of Godfather work in-cohesive.
