MB doesn't have a service interval on packing wheel bearings because the labor for the service would cost more than the bearings that the service would save.
Besides on the early cars the bearings were easy to pack when the brake rotors were changed which was more often than the anticipated bearing grease life.
We have for years packed the small outer bearing at 30k services. Of the hundreds of wheel bearings we have replaced on the front of MBs probably better than 90% were the small outer bearing. This bearing can easily be removed without disturbing the brakes.