I found this a little before I read this post.

At least Bill Bonnanno thinks Vito Corleone was modeled after his father.

Bonanno salutes Puzo
Family was model for bestselling 'Godfather'

By Jon Kamman
The Arizona Republic
July 3, 1999
Bill Bonanno of Tucson, whose family was the model for The Godfather and whose own memoirs as a mafioso have just been published, saluted Mario Puzo on Friday for having "set the gold standard" for books and films depicting organized crime.
"Mario had a lot of help in the sense that he grew up on the West Side (of New York City) and could put on paper what he saw and heard. He did it very masterfully," said the 66-year-old son of Joseph Bonanno, the archetype for Puzo's fictional Don Corleone.
"That piece of material has set the gold standard of this genre," Bill Bonanno said of The Godfather.
Puzo's work was "not a distorted version - never" of the mafiosi culture, said Bonanno, who objects to the term "Mafia" as a law-enforcement creation that strips the Sicilian mafioso term of its honorable meanings.
"I thought he depicted a story of tradition and a story of values and - no pun intended - really a family story," Bonanno said. "He left something that will endure."
The elder Bonanno, who was the so-called boss of all bosses of New York's five crime "families" in the 1960s, is now 94, alert and comfortable in Tucson, his son said.