It is already painted when you order the bumper from the factory. Are you looking for a touch up kit for it or are you looking to paint something else the same colour?
The colour is "Platinum Grey Matt" but I can't find a code for it.
Should be the same problem as with my anthracite rs4 style wheels that I ordered.
I wanted to colorcode my mirror caps in the same color.
Audi told be that they dont have a colorcode. Not even a matching touchup stick.