Other mistake: When one of the artists throws a lump of clay during the clay fight, another artist ducks and the clay falls downwards, but it still manages to hit Curly on the top of the head.
Other mistake: After Moe has painted the cop's face with a paint brush, the Stooges walk across a floor that is covered with wet black paint, yet when they are in the room in the next shot, they leave no footprints on the floor.