Didn't he also wrestle as Curly Bill briefly? What the hell was that? A veiled reference to Bill Watts?
Yup, when he was aligned with the West Texas Rednecks. No idea the reasoning behind the name.
Maybe this?
William Brocius (c. 1845 – March 24, 1882), better known as Curly Bill Brocius, was a gunman, rustler and an outlaw Cowboy in the Cochise Countyarea of the Arizona Territory during the early 1880s. His name is almost certainly an alias, and there is evidence linking him to another outlaw named William "Curly Bill" Bresnaham who had committed an 1878 attempted robbery in El Paso, Texas.