Factual error: In the saloon at night, Ben Wheeler says, "I can't afford another Workers Comp claim". Workers compensation wasn't started in the United States until 1902. (00:10:25)
Factual error: In the final showdown between Julian and Slade, Julian fires a single warning shot, to Slade's belly. Then when Slade draws on him, Julian turns and fires 12 rounds. That's a total of 13 shots from a pair of six shooters.
Answer: It appears to be a woman standing up and reaching for something in her wagon. As the camera pans away, this stool can be seen thrown and landing - breaking apart.