Other mistake: The film is about a gang of Confederate soldiers after the Civil War, so a black man in the gang would seem a bit out of place.
Continuity mistake: When Curly Bill is shooting up the town while drunk, he fires about 10 more rounds than his six shooter can hold without reloading (so too many shots even if he had a second gun), and still has a round remaining when he shoots Marshal Fred White. In the 1880 court hearing held after Marshal White's death, Curly Bill still had 5 rounds remaining in his pistol.
Revealing mistake: In one of Pickett's charge scene the bayonets are obviously rubber.
Continuity mistake: In the prosecuting attorney's speech in the first courtroom scene, the judge's house of cards is no more than 2 levels high (a base level with a peak) [0:2:20]. In the close-up shot of the judge, the house of cards changes to 3 levels high (2 base levels and a peak)[0:2:35]. When the scene focuses back on the prosecuting attorney, the house is back to two levels of height[0:2:39]. (00:02:20)