Our guy has the more modern multi link rear suspension found on pretty much every MB from 86 or so.

So far I've found at least the W140 S class has larger bearings / axle spline / different rear suspension.

Anything from a W201 W202, W124 , R129, and others should fit as long as the wheel speed sensor ( or lack of ) is taken into account. The parking brake cable may be different and there may be a dust shield difference. Caliper mountings may or may not be the same, I've never checked. I realize this sounds like nothing is the same however the basic design didn't change much over the years.

Below is a USA nation wide salvage yard search, it will give you some idea as to what will fit. The list isn't absolute as sometimes cars are miss categorized by the salvage yard but it will give you some idea what to look for.

Main page
Car-Part.com--Used Auto Parts Market


Using your car info and selecting " rear knuckle / stub axle "
Search Results