I don’t want to rain in your parade (and mind it doesn’t rain into that lovely case) but guns generally last better in stored in a well ventilated gun cabinet.

Old cases can have unsuspected moisture lurking in baize or canvas accounting for otherwise crisp guns found rusted on the right cheek of the action.

I’d keep that case interior exactly as it is. I would bet that you are right in thinking it was the original for that very gun.

A fabulous find - All Praise to Joe from Charlotte!