Perhaps I'm not correct about it being in the Saga, but that scene is in one I dvr'd Bravo this year. I believe it was referred to as the "Novella," but how much that differs from the Saga I could not state.

On a side note, one scene from the novel that I never understood why it wasn't filmed was the scene in which Sonny proposed to kill Sollozzo and Sonny laughs uncontrollably. In the novel, Mike confronts Sonny and tells him to stop laughing, thus reminding everyone in the room of the similarity b/w Michael & Vito. Sonny explains "I'm not laughing at what you said, but how things turned out...All it took was a sock to the jaw. Howdaya like that?" I always felt that this scene would have added to the film.