Factual error: Captain Love's revolver is a Colt Buntline. This model wasn't released until 1876. The movie is set in 1841. He should have been using a Colt Paterson, which was invented in 1836.
Suggested correction: The pistol that Captain Love is using IS the Colt Paterson. You can see this by going to timestamp 1:58:17. If you look at the profile of the weapon in his hand and compare it to pictures of the Colt Paterson, you can see it is a Colt Paterson. The Colt Buntline does not have the same profile.
At the end of the movie Captain Love does have a Colt Paterson, but in the beginning of the movie the pistol he has is a different model. The first pistol looks a lot like a Colt Buntline.
Revealing mistake: Stuntmen can be seen in various scenes. Examples include the opening fight at the plaza, the fight at Montero's courtyard, the horse chase scene and the final duel between Montero and Diego.
Suggested correction: This is too vague. You need to specify the specific shots they can be seen in and which actor the stuntman is replacing.