without doubt, pickups are handy and handier with a proper hitch. One thing to keep in mind, in Europe towing with cars was the norm, pickups, SUVs and the like are a relatively modern concept within the past 25-30 years, prior to that people towed campers and trailers with their cars. Mercedes had two hitch manufacturers one in Germany (Oris I believe) and cannot recall the name of the US mfg one, but they were indeed factory/dealer installed options.
MB rated their tow limits based on the smallest engine in the range for all engine option in the range. The tow limit for a M103 260SE/300SE is 750 kg unbraked and 1900 kg braked. The W126 hitch like that of the w124 hitch for the wagon was bumper mounted with two long trailing support bars that would engage further forward on what could be called the "formed frame rails" of the unibody structure, so we're not taking about a purely bumper mounted aka "u-haul" hitch. The difficulty would be in finding the correct hitch, so getting a beater truck may be the realistic option. The spec card from another post is shown below:
