“The No-Gun Gunhawk” by L. Ron Hubbard
Publication date: November 1936
Original publication: Western Aces
Story description: Forced to change cloths with a masked rider, the son of dead gunslinger is accused of a murder, but escapes to exposes a plot to rob a bank and steal a valuable ranch.
Currently available as part of the Stories from the Golden Age series, in the title King of the Gunmen.