These photos show the factory option Oris Roof Rack installed on a 1992 300CE Sportline. The “Alustyle Basic carrier bars”, part number B6684 8451L, are attached to the built-in roof mount fittings that came stock on the Model 124 Coupe. The permissible load limit for the roof rack system is stated as 100 kg (220 lbs).

Various attachments to the basic carrier bars are available for securing skis, bicycles, kayak, luggage and other items. There is an outfit in Toronto that advertises in the The Star magazine (Mercedes-Benz Club of America), called German Motor Imports (416/ 652-1404), that supposedly sells the carrier and attachment bits, new and used, from the OEM supplier, Oris of Germany.  I have never used them, so I don’t know anything about them.