The storyline of Ruddy being shaken down by Gallo, after Joe Colombo is shot, but not having to pay because the Colombo Family kills Gallo mirrors the storyline from the novel where Johnny Fontane also gets shaken down by the union after Don Corleone is shot while he produces his first movie, but doesn't have to pay because the Corleones kills the union boss.
Joey Gallo's murder let's Al Ruddy off the hook from paying extortion money. The production of The Godfather ended in August 1971. Joey Gallo was killed on April 7, 1972.