The artillery pieces at the fort are set off by putting a burning torch to the cannon's touch hole. But artillery at this time were set off by placing a friction primer in the touch hole. A lanyard was then attached to a looped serrated wire which ran through a tube filled with fulminated mercury. When pulled, the serrated wire set off the fulminated mercury and a flame shot down the tube and ignited the main charge in the cannon barrel, thereby propelling the projectile toward the target.
The French troops in this film are using Henry rifles. But as the French presence in Mexico was in direct violation of the Monroe Doctrine, the Federal government would have prevented the exportation of Henry rifles to the French army in Mexico, as they did countless other arms. In actuality, the French army in Mexico used P1851 Minie or M1859 Chasseur rifled muskets. These weapons look NOTHING like the Henry rifle.
Nighttime scenes were filmed using a filter to darken the scene. But the sky is still blue and distant objects are clear and well defined, whereas the true night sky is always black and distant objects are obscure and fade into the darkness.
Since the Apaches were watching the fort, they would have seen what was happening and either attacked the patrol staking out Jim and Lee, or rescued them once it was done.
Claudine wears very modern-style eye make-up.