Leave it as-is, IMO. If that rifle could talk, what tales it could tell ...
Maybe those scratches and dents and worn bluing will help it tell some of those tales to your grandson.
Just saw a segment on Jay Leno Garage and was astounded by the money that rust-bucket antiques are selling for nowadays. They had a Dodge Charger Daytona that was nothing but rust with destroyed interior that went for $90,000 at auction. It wasn't even good for complete frame off restoration.
As classic car owner (58 Impala survivor), I couldn't see one part that was salvageable, but collectors are now into these classics and antiques just because they are entirely original. It was so bad that Jay didn't even want to sit in it! You wouldn't either if you saw it.
Maybe there is a growing market for beat up old guns in original condition, also.