Charles E. Boles was the historical figure known as Black Bart, and he reportedly held up 28 Wells Fargo stagecoaches in Northern California before he was captured in 1882. The real Boles operated alone, used an unloaded weapon, and often-times he left poems inside the strongboxes he had looted. After his release from prison, he disappeared. His place and date of death is unknown. Update 2/2022; According to Wikipedia, Black Bart left only a brief poem at two different robberies.
Edmond O'Brien was originally cast in the role of Lance Hardeen but he was replaced by Jeffrey Lynn.
The script by Luci Ward and Jack Natteford is based on a true story.
It is generally believed that Boles' shotgun was empty. This has been debunked. Although he never shot anyone, his shotgun was loaded.