Both the style of lights in the picture are Euro lights. The round ones are indeed bulb and mirror lights and they were used on 123's other than the 280 engined cars, which, being considered the top of the heap as it were of 123's were given the squared lights similar to the S class cars. And I believe the square ones are also bulb and mirror though as I never had to replace a bulb in mine I cant say for sure. And in answer to the original question. On 123 300D's the round ones are the correct Euro's.

- Peter.

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2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S