Other mistake: When Harrison Ford and Gene Wilder are being chased by the bad guys, they're discussing whether the sun is setting, and there is a shot of the sun going behind a ridge. When the actors are shown again they are in full light, and not in shadow as they would be if the sun was going down, even though Gene is bobbing up and down as if he's making the sun go higher or lower by the position of his head. (This is so that they can remount once the sun has gone down, as the Jewish day of rest will have ended.)
Other mistake: Handsome and Charming head out of Snakes End (followed by the newlyweds) and begin their long journey. It then cuts to Cactus Jack before he begins the journey, and at the start of this shot as he places Whiskey's bit, we can see the signpost with three wooden arrow signs and the hillside behind him. This is the same location where Cactus Jack lays trap number seven, named "the tunnel in the hillside," on the next day during the journey; noticeable when Handsome and Charming arrive. (00:28:35 - 00:54:45)