Revealing mistake: When Madame gets off the carriage, Frou-Frou winnies to get her attention. Madame then proceeds to feed her. Frou-Frou eats from her hand. However, if you look closely at Madame's hand, it is empty. (00:03:05)
Revealing mistake: During the Little Bighorn massacre one of Custer's lieutenants turns to address Custer and is struck in the back with an arrow, and the thick pad or board is visible under the actor's shirt.
Revealing mistake: That isn't Joan Sims in the shower as seen from above. The stand-in doesn't remotely resemble her.
Revealing mistake: After Clint has shot the 3 would-be rapists, he is rifling through the pockets of the dead men. As he checks the pockets of the first guy he shot the "dead" guy in the background is breathing.