Make a black Stetson from Sculpy/Makins Clay, put it on William Hartnell's head!
The Gunfighters was the eighth story of Season 3 of Doctor Who. It was Doctor Who's first attempt at a western, and, indeed, the first story in any medium principally set in the United States — though the First Doctor had briefly visited New York City in The Chase. William Hartnell would later claim that the Wild West setting was his idea, a statement which was confirmed on the DVD bonus features.