You have one great mom. She gave your dad a gift that he could later give to his son. I hope you hang on to that gun and hand it down to one of your own kids or a nephew or niece.
I would not worry about the value of your gun since it sounds like a family heirloom that would not be sold. I'd shoot it and maintain it.
I have an early Browning Sweet 16 in nearly perfect condition. It has one "character mark", a worn spot on the barrel created when my dad used to carry the Sweet 16 across his bicycle handlebars. That mark is staying there for the next 15 or 20 years that I have the gun. At that time, my son gets the gun and he can decide if he likes that "character mark" too (so far, I have not accidentally added any character to the gun myself).