Factual error: Throughout the entire film the wrong holsters are used. They are wearing "drop loop" holsters but they weren't invented until the 1930s.
Factual error: During a shootout at the end of the movie, one of the gunmen with a rifle is wearing a wristwatch. (02:00:00)
Factual error: The movie begins at the end of the Civil War, 1865; it then moves ahead 7 years, to 1872 in Wyoming. Several characters are wearing gun belts with cartridges on the belt. The pistols are Colt Peacemakers probably .45 cal. The problem is that the gun and cartridge were not introduced until 1873 and would take several years to become commonplace.