Patek is one of the very very few watchmakers able to service and restore every watch they've made since day one.
I used to own a sample made back in 1881, according to the archive it was sold as a stand alone movement so it explains the funny US made, VERY pink 18k wrist case. When I sent it back for service, they gladly offered a full restoration on the movement, dial and hands, but they , understandably, refused to touch the case reasoning that it was neither made nor cased by Patek . ;-p but they agreed to add a remark to the archive after examining the case and agreed that it was original and not a re-case job.