At the part when they hold up the train for the second time the modified handcar has the dust from bullet hits on the armour plating long before the horse rustlers started firing. The next shot the marks are not there and appear as they shoot at it.
The helicopter in the final action scene has a green colour scheme when it first takes off with Bus Carter in it. When Hannibal and Murdoch take control of it, it has a blue colour scheme.