Factual error: This Warner film concerns a pair of post-Mexican War, new-style percussion revolvers stolen from a travelling arms dealer and used in a crime spree. The criminal was unbeatable because of the overwhelming firepower of the guns compared to the single-shot handguns used by everyone else in the film. The title guns used throughout the film were a pair of Colt Dragoon revolvers, in caliber .44. Colt didn't manufacture a .45 revolver until the metallic cartridge era, in 1873.
Continuity mistake: When Annie finishes her song about "doin' what comes naturally," she grabs her rifle and uses the butt to shoo the children towards the house. The man she is talking to is close enough that she could touch him with the gun if she wanted too. The shot changes to a longer shot of the same view and the man is suddenly 5 or 6 feet further away, where the gun would no longer reach him.
Continuity mistake: At the beginning of the cartoon, Tom lifts a flower pot to reveal a cowering Jerry. But after Tom has caught Jerry with his lasso, he pulls him back but the flower pot is nowhere to be seen.