There is no doubt whatsoever that Holland makes fine guns. Is a Holland as best as it can get? I am convinced it is not, a shotgun can be simpler, more robust, less costly and still provide that fine balance and the ergonomics associated with a bespoke gun.
It can be done. Perhaps the result will not have the cache of a London address, or the complexity of a sidelock with its 19 bits per side. For this reason I respond to the original poster that new can be better than old. It is a technical consideration.
Bluing is not a big deal, but is it something that should be necessary after rib relaying, and should complete rib relaying be necessary even if a small bit of the rib is loose? To some that chain of events means deficient design.
