Before you do anything, put the ramrod down the barrel and mark it. Then lay it along the barrel; the end of the ramrod should be real close to the flash hole. If it is 1"-2" inches from the hole, chances are the gun has powder and ball in it. Water will kill the powder for sure if it hasn't already. But the water must get to the powder either thru the nipple or down barell past the rust. Be safe first!
The barrel bands look like they were driven down for friction fit, with a screwdriver with the nicks in the front, and they have been removed at least once by the nicks on the back. Metal to wood fit is extremely poor in the pictures, and may be the cause of the cracks, not just age. If I had to guess, I'd say it was a trade gun, or maybe manufactured or made up in one of the Pakistan / Afganastan local back alley gunshops.
For me, I wouldn't put much time in on it before I hung it over the fireplace. Just my opinion tho.