Headlights--the US spec used stacked sealed-beams, the Euro has a solid vertical lens over the headlight and directional/parking light, with no other light between grille and headlight assembly.
Instruments--metric units, not English.
Upholstery--Euros offered cloth;
AFAIK US had only leather or tex.
Ultimately, serial number and contacting the MB Classic Center in the US--not hard; they'll respond online and can give you the full build card information on your car.