I'm not sure how many people called the tune Mockin' Banjo, but the Kentucky Colonels did, circa 1965. I think the guitar (Clarence White), the banjo (Billy Ray) and the mandolin (Roland White) trade breaks rather than "duel", but I will listen tonight to be sure.

Clarence was known to change the name of tunes, sometimes humorously, as Beaumont Rag is called Julius Finkbine's Rag when he played it.