I did some digging, and the champagne seats are interesting.
Accoring to the bmw parts catalog, there is only one champagne seat, for prefacelift cars, facelift cars and z4m
Individual walknappa champagne with interiorcode LLCM and LPCM (one is extended the other not), both with the same partnumbers.
52107918237 for the backrest.
However in the bmwzroadster site you see this interior with the z4m:
And at the z4 individual this interior:
So which one has which partnumbers if there is only 1 traceable partnumber?!?
On the bmwz4 roadster they state LLCM/LPCM also for that z4 individual interor.
So that is really dodgy. One of those interiors has interior parts that have no traceable partnumbers (big bummer if you want to replace if one is broken/damaged....)
The parts also dont show a revision date or so. same partnumbers since introduction. OR is one of those interiors NOT champagne (and then that bmwz4roadster site is incorrect with the data)