Dennis Rush, who played Lon Chaney Jr. as a youngster opposite James Cagney in Man of a Thousand Faces and one of Opie’s pals alongside Ron Howard on The Andy Griffith Show , has died. He was 74. Rush, who was diagnosed with leukemia last month, lived in the San Diego area and died Saturday on the way to the hospital, actor-musician Keith Thibodeaux told The Hollywood Reporter . (Thibodeaux played Johnny Paul Jason, another of Opie’s friends, on The Andy Griffith Show , though he’s best known as Little Ricky from I Love Lucy .) Rush also showed up from 1960-62 on seven episodes of Wagon Train — John Ford directed him in one — and from 1962-63 on three installments of Laramie . Both were Westerns from Revue Studios and NBC. The freckle-faced Rush made his onscreen acting debut as Creighton Chaney, age 4, in Universal-International’s Man of a Thousand Faces (1957), starring Cagney as silent film star Lon Chaney ( The Hunchback of Notre Dame , The Phantom of the Opera ).…