If it were mine---I'm not a collector---I would keep it as it is. You are fortunate in owning a gun that's been in the family all these years.

If a gunsmith said it was in good condition, I'd buy some light loads, take the shotgun on a family outing, fire a shot to celebrate a great provenance.

Just think of it: "This is my grandfather's gun." "Ever shoot it? "Of course. It's been in the family for X years." You're a lucky guy!