A piece of American history has come home after a long absence. A .78-caliber smoothbore musket, stolen from the Valley Forge Historical Society (now the Museum of the American Revolution) in 1968, has been recovered and returned to the museum. The musket, believed to have been used by a Continental soldier during the Revolutionary War, was one of several firearms taken during a heist over 50 years ago. The FBI, working alongside the U.S. Attorney’s Office for the Eastern District of Pennsylvania, the Montgomery County District Attorney’s Office, and the Upper Merion Township Police Department…