Are the seats and door panel parts of the 280 sedan interchangable from year to year?

It's not the engine that matters for interior interchangeability 280, 250 etc. It's the series. 114, 115, 123 etc. Interiors of all cars withing a series are interchangealbe with all other cars in that series.

So seats from a 123 series 200, 230, 240D, 250, 280, 280E, 300D are all interchangable as are the door panels etc.

- 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