im a historic restorer for landmark buildings(churches etc) and do a few classic car now and then, some instruments as a hobby the same rule should apply here if you can conserve/preserve the drum then thats what you do with any thing old and analyze (sometime we do microscopic analysis on the finish if it tite we clean it and oil, polish/wax it touch up and blend were u can if not re re do it ... with anything else whether its a historic home car or musical instrument the rule of thumb is if its is degraded beyond repair as with some classic cars we replace parts with nos or good used oem so as with a rare drum the rarer of course the more specific you want to be in the restoration if the rap is gone but everything else is there and restorable then to make it right you find a rap close as possible even from the original co. if possible finding raps form the era as there around u have to be creative in the search and rescue then it s vintage correct that is not wrong to do especially if its nos raps (new old stock)
or vintage manufactured or oem in good used condition but if none of the above then you go to aftermarket as close as possible either for keeping and playing or for reselling not everyone out there is a purist granted as time goes by museum pieces are rare and hard to come by just be honest about it and someone will be glad to own it thats all i got to say about that
