I think you will have to get the complete assembly from MB, not just the lens cover. There is a Hella part number (shown in photo) on the fog lamp. The lens cover does not seem to be a separate part. The only MB part number is on a label attached to the cable. The part number is "A 230 540 38 05".
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!