Visible crew/equipment: In the shot where Dirty Steve is on his horse, he asks, "Hey Dog, did you see the size of that chicken?", and then he fires his shotgun. You can see someone's hand come up to grab the reigns of the horse. (00:43:25)
Visible crew/equipment: When Buckshot Roberts is going into the outhouse there is a sequence of shots that show Billy the Kid, Dick Brewer and Dirty Steve hiding behind a pile of logs. In almost every shot where these three are seen behind the logs you can see a camera tri-pod leaning against a fence. The sequence lasts over a minute so you have several chances to plainly see it. (00:47:05 - 00:48:15)
Chosen answer: He may have. When Billy started whistling, the bounty hunter's face changes. He continues to speak to Billy in a dismissive tone, but does eventually pull the trigger (although Billy had unloaded the pistol). Hard to believe he would just shoot some mouthy kid in a bar.