Factual error: The narrator mentions that the Cheyenne tribe split in half in northern Nebraska. The scenery would suggest otherwise, as there are no mountains that high in Nebraska.
Continuity mistake: After the Baxter/Rojo dinner, the background changes from nightime to daytime at the cemetery, then back to nightime again when Clint kidnaps Mirasol.
Continuity mistake: At Molly's party after returning from Europe, the Duchess is introduced, and everyone bows. The shot shows Molly reaching for her neighbor who's standing straight, to bow down, and she does. Then there is a long shot showing the crowd, and the neighbor is again standing, and then you see Molly reach out for her again as she just had.
Continuity mistake: When we see a close-up of the meter, there is a box saying "10 Centavos for One Hour." The words were not in the box in the previous shot.
Factual error: In a scene set in 1871, several newspaper articles get printed on Moe's face as he falls onto a printing press. Curly Joe reads that "AT&T is splitting two for one." American Telephone and Telegraph Company was founded in 1885.