Great advert. I used to listen to Curley Bradley impersonating Mix on the radio in the late 1940s. Shredded Ralston is still available in your local food store, but you know it now as Wheat Chex.
If I recall, Jim Harmon tried to revive the Tom Mix radio show in the '70s, again with Curley Bradley.
You're correct! When he lost the rights to MIX (I think) he also developed a show called THE RADIO SQUADRON that starred Curley as himself alongside thinly veiled variations of other classic radio heroes including Captain Midnight. Former Superman Kirk Alyn was also in the cast but I can't recall who he played. Jim Harmon, btw, would many years later be my editor on the first professional sale I ever made as a writer!