I disagree on the rear coil springs. I'm fairly confident that all W124's chassis cars, regardless of self-levelling suspension still have their coil-springs in the rear.
My wagon and 500E which BOTH have self-levelling also have rear coil springs
I would check to see if your rear struts have plumbing going to it. If it has plumbing, then you have self-levelling (unless you're running air shocks which I don't think anyone with a W124 would do).
1988 360TE AMG