I haven't seen the part number but I believe that it's more than just plug-play a module. It's a factory installed option and although I'll bet you could buy it at a later time, it would probably be so expensive that most will buy aftermarket retrofits.
Worst case, the wiring harness will even be different. VW does dumb stuff like having different wiring harnesses for small differences in optional equipment instead of having the same wiring harnesses with a few unused plugs. I would think having less parts = less inventory but I guess they've figured out a way to make the numbers work.