Two part numbers are available for RHD cars:
1.
8P2 713 141 C QBZ -- perforated leather. My knob.
This is RS6-only knob.
2.
8P2 713 141 C SKH -- non-perforated leather. Used on RS6 cars with heated steering wheel (PR code 2ZD). I don't think there's heating element in this knob, since price difference isn't noticeable. It is actually cheaper. Most probably they just wanted to match style of heated steering wheel, as heated steering wheels are made of non-perforated leather. Picture of LHD car with non-perforated knob is here:
http://forums.audiworld.com/showthread.php?t=2790851
This knob is actually used in the following cars: Audi A3, S3, A6, S6, RS6 and Q7