Hey Buckingham - I've nothing new to add, the others have already pointed out that the sideplate is recycled from an India pattern Bess, which means it can't be rev-war period. Still, it's a very nice musket assembled with some earlier Bess parts, like the barrel, lock, and triggerguard. It's got nice lines, which helps its value regardless of its era, and makes it more attractive than a lot of cobbled together muskets of the same period.
-Eric