Yep looks like a springfield-U.S. Model 1863 Springfield Type II Rifle Musket.
Take Care,
Pete, This is the last model of US military Percussion Musket produced by the National Armory in Springfield, Mass during the Civil War. Known as the Model 1863 Type II, it was produced from 1864-65 with a total production just over 250,000 units. This one was built in 1864 and is a good solid example of the Model 63 in .58 Caliber with 40" barrel. True to the Type II, it has 3 barrel bands secured by band springs.