Just guessing, but I bet the one in the center is a Colt Walker or Dragoon, because of the size. I have to agree the musket is a prop. With 4 revolvers, he probably had a hard time moving, an extra 10 pound musket and cartridges woud be a hinderance.

Try these sites:

Sharpsburg Arsenal
Shiloh Relics
Union Drummer Boy
Horse Soldier
Dave Taylor Antiuqes

All five are knowledgeable, honest and helpful. They could
probably ID all the weapons in a couple of minutes. By the way, please let us know what they are.