In the final studio set scene, Bart Maverick and Johnny Bolero depart on a palomino and dark horse respectively. However, as they ride into the distance, the two horsemen, again taken from another film, are on two dark horses, one with a white tail.
In the opening scene the 'Overland Stage Line' stagecoach is a different coach to that attacked by the 'Apaches' (obviously taken from two different films!) and yet again to the studio setting coach from which the occupants appear following its overturning.
At 35:40 an airplane can be heard flying off camera.