Yes, Profaci was one of the original heads of the NY five families and Clemenza was (in the film) just a Capo. But in the novel, Clemenza becomes Don of the Corleone family. Now, Profaci was very close to Bonanno just like Clemenza was very close to Vito (I mean very close in both cases). Bonanno and Profaci engineered the ill-fated attempt to eliminate the other NY Dons and that is similar to the assistance that Clemenza (even thought he was just a capo at the time) gave to the Corleones (albeit to Michael and not Vito) to eliminate Barzini and Tattaglia (in the novel) and all the NY dons in the film.