The color code of your car should be on a steel plate under the hood near the lock of the hood. This identification tag (OEM MB) contains several numbers; one of them is the code for the chassis color. If you cannot find what I mean, I can send you a picture by mail with the mentioned number to look at...
Each chassis color comes with a certain (known) contrast color code for the plastic panels and bumpers. The color-codes for the chassis exists out of three numbers, the contrast colored panels and bumpers have a four digit color code (if I remember correctly).
The dealer should be able to give you the color-code by VIN#.
Half matt/partly matt, it doesn't matter that much as long as the repainter knows that the plastic contrast color is not glossy and is not completely matt!
with a minor 600+k