Wheel Accessories

Ok. Does anybody know what the correct colour is for the RS4 wheel centre cap? On some cars it is black(like on my replicas)but on others it is silver. I'm confused. What colour SHOULD they be? I've had a look at a few RS4s and they have confused me as they are different colours on the cars I've looked at. I want mine to look as original as possible.

Second. You know those plastic wheel nut covers, locking wheel nuts and the wee set of tweezers that is kept with the spare wheel? Will I be able to buy them from Audi? Mine are missing from the car.