This is a rifle passed from your father to you.
Can you conceive of a time that you might want to sell the rifle, or do you see it being passed on through the family?
If you may sell it some day, leave it alone. If you plan to keep it in the family, tap it, install modern rings and a scope, and make the rifle useful for you. Would you rather think of you father every time you pull the trigger on a rifle you can use, or every time you open the door and look at your safe queen? Yes you may devalue the rifle, but we aren't talking about a Purdey here.
The flaming begins in 3..2..1..