There are no marks on your Pattern 1853 Type 3, Rifled Musket, other than some standard British proof marks (on the barrel} and regimental stamps (on the butt plate tang}. Back in the 1960's they were shipped here in cargo vessels, for the 100'th anniversary of the Civil War. "Ye Old Hunter" in Alexandria even had their own dock on the Potomac. I remember digging through buckets of parts to build your own "Trap Door" Springfield for .50 cents a pound, while watching them unload F-84 jets. "Hunters Lodge" in Tennessee was also in the game. The NSSA {North South Skirmish Assoc.} and re-enacting were gathering steam around that time as well.
As a fellow Virginian (we love old stuff!!} I'd suggest you might want to clean it up a little with a good gun oil {Ballistol} and furniture polish {Kramer's Best}. Leave the rear sight alone. It has been reversed, to prevent the ladder from being slammed down due to recoil. This would indicate to me it was well used in the past.
Pass it on and keep it in the family. IMHO.