J.J. Jackson proclaims in a conversation with Sam and Arlo that the father of Billy the Kid , William Bonney Sr. was buried in Coffeyville, Kansas. In reality There was no William Bonney Sr. because William H. Bonney was just an alias. Billy's real name was Henry McCarty and his fathers name was Patrick McCarty. Patrick McCarty's grave is at the Mt. Hope Cemetery in Kansas City Kansas. Not in Coffeyville Kansas.
The back blast of the M9-A1 recoilless anti-tank rocket launcher would have certainly spooked the horse standing behind Billy when he fired the weapon at the truck. More than likely at that distance the horse would have been severely burned by that back blast. However the horse showed no reaction whatsoever.