I have been reunited with my sources. In a book on Kentucky rifles of North Carolina is a flintlock with a similar lock bolt plate. It was made by Timothy Vogler of the Salem school of gunmakers. It dates to the late period of flintlock guns, so I would guess 1830's to 1840's. On the lock plate is stamped, "ROGERS BROTHERS WARRANTED." My guess is that the lock and lock bolt plate on yours were not made by the gunsmith. Also this is not proof that your gun was made in North Carolina.