The 80 240D and 84 300D have a different electrical plug on the rear. The ignition switch is also different.
The 80 has 8 pins, and the pins are exposed, and is a plastic pin with one flat side. maybe 1/4 in wide.
The 84 has 7 pins, and they are recessed with a hooded cover the plug fits into. the center pin is a female slot .
the steering lock assembly is the same on both cars.
I have both that I removed from my 80 240 and 85 300D.
the 80 is $83 and the 84 $40.