In the book, the gangster whom Vito Corleone arranges to be killed in a restaurant is called "Maranzalla." That's close to "Maranzano," but in the real-life episode, Joe Masseria was killed in a restaurant, Salvatore Maranzano arranged the killing through Lucky Luciano, Masseria's then-second in command. But Luciano didn't pull a trigger: he arranged for his pal, Meyer Lansky, to assemble a hit team, which included Samuel "Red" Levine and Bugsy Siegel.
There's another parallel in the book: Puzo wrote that Sonny made his bones and showed his "genius for urban guerrilla warfare" after the Don was wounded by a "free-lance Irish killer" who penetrated the Don's shield "with Emerald Isle elan." The parallel is that, following his elimination of Masseria, Maranzano contracted with an Irish free-lance killer, Vincent "Mad Dog" Coll, to assassinate Luciano, whom Maranzano had placed in charge of Masseria's family. Luciano struck first: he reached for Lansky, who reached for Levine & Co. They burst in on Maranzano's office in the Grand Central building, flashed badges that identified them as Treasury agents, demanded to see his books, and shot and stabbed Maranzano to death. The story goes that, even as Levine & Co. were fleeing down the stairs, Coll was in the lobby ringing for the elevator to take him to Maranzano for his final instructions before killing Luciano. That's how he got to be called "Lucky."
Though it's not in the book, there's yet another parallel in Part II of the Saga, with the Frankie Pentangeli garrotting: In 1960, the Gallo Brothers (Larry, Crazy Joe, Albert "Kid Blast") defected from the Profaci Family and went to the mattresses. The following year, Larry was garrotted in the back of a nightclub on Utica Avenue in Brooklyn, but was spared when a cop happened by. The Daily News ran an unforgettable photo showing cops leading away Larry, with a big red line around his neck. I guess the Rosato Brothers were the Gallo Brothers, but the garrotting roles were reversed. Amusingly: Crazy Joe was a publicity hound even then. He actually invited a reporter from Look Magazine to visit and write about him and his gang at the mattresses in Red Hook, Brooklyn. The reporter wrote that he encountered a dwarf, Armando (Punchy) Iliano, in the Gallos' hideout. "What's he doing here?" the reporter asked Joe. "He's our dwarf," replied Joe with a straight face, as if to say, "Don't you guys at Look have a dwarf?" I never thought of Crazy Joe as a wit until that point.