Northwestern Pacific Railroad Historical Society has an 1869 Central Pacific wood coach, #29, it was later NWP #123, then a MW car, and then detrucked and used as a house:

http://www.nwprrhs.org/coach-29.html#c1

They are returning it to its original configuration as a CP car rather than its NWP setup, but it was essentially tubed long ago and is lacking all of its interior fittings, so they aren't destroying any of the car's in-use fabric. Their situation is different than with the NV car, the body of the NWPHS car is actually in great shape having been under an added metal roof and in the shade most of the time it was a house.

Given that this car exists, I see no reason to return the NSRM car to a CP car.