I have the 1983 300SD and my switches are soldered in and
not a connector. Rotten luck.

A later switch will be a connector, if you get it that way ask for them to cut
some of the harness and then you can splice them together.

I ended up pulling internal parts from a good switch and rebuilding mine.
The little plastic arms broke and the knobs came off ours.

To use memory function (which you say doesn't matter) you would need the
seat motor assembly from the car with memory seats.

To simply use the switches and not have memory functions should be okay.

You will have to map out the wires, which I think has been done here
before.

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80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250