Johnny Mack Brown? I, only, remember him from old movies on TV. I am, however, old enough to have seen Lash Larue and the Durango Kid on the big screen (Whip Wilson was a pale imitation). Cowboy movies were all B features back then. I didn't see Hoppy in the theater but I followed his adventures with his sidekick, Lucky, on the tube.
Cowboy sidekicks are an interesting group. There was Al "Fuzzy" St. John (He had been one of the original Keystone Kops), the ventriliquist, Max Terhune (and his dummy, Elmer) and, of course, the ever popular George "Gabby" Hayes (Yer dern tootin').
Johnny Mack Brown, who had been an All-American football player, was often teamed with Buck Jones and Bob Steele. They were called The Three Mesquiteers. You may remember Bob Steele as the heartless killer, Canino, in "The Big Sleep" or from his continuing role in the TV western spoof, "F Troop"

                   Mike.