The old Purdey case that houses my (Purdey) muzzleloading double 16 bore from circa 1860 has developed a problem in one of its compartments. The top 1/2 inch edge of the felt at the butt end of the stock has come loose. I was going to glue it before thinking of its age and wondering if that had any impact on how I would go about affixing it.

Anyone have experience repairing such things after 150 years?