Pat gets tortured for a long time with a bullwhip used on his back, but his shirt isn't even torn afterwards.
When the wounded marshal sees a gunman about to kill Buffalo Bill, he fires his shotgun at him. However, the sound that comes out - obviously added in during post-production - is that of a pistol.
Although the plot has well-known actual western figures Pat Garrett, Wyatt Earp, Bat Masterson and Buffalo Bill fighting Butch Cassidy's gang, in reality, by the time Cassidy had gathered his now-famous Hole-in-the-Wall Gang, Garrett was dead, Buffalo Bill was touring with his Wild West Show, Earp was prospecting for gold in Alaska and Masterson was a sportswriter for a newspaper in New York City.
One outlaw tells the gang that Bat and Wyatt rescued Pat. But the guy was inside the cabin and could have only seen Wyatt. No way he could know if Wyatt had any help, or who that might have been.