Other mistake: Fleeing with Little Creek from the fort, Spirit destroys small railing to free horses tied to it. But after the pole gets torn off, it leaves an empty space on the ground, without any hole or at least broken remains.
Question: Why does the Colonel let Spirit escape at the end of the movie? I know it's meant to be a sign of respect. But why would they respect each other? In my opinion they have no reasons to have mutual respect.