For the moment assume they are expensive rather than unskilled at that dealership. You can inspect and repack your front bearings yourself for possibly just the cost of replacement grease. Use threads in the archives for the proper method.

The mercedes front wheel bearings do not seem to require repacking as often as older american rear drive cars did. This does not mean they are maintenance free for their expected life. Anytime you buy an old car just assume they have not been done for far too long and do them. Really a minor job. After the first time it is like falling off a log.