The W 126 will also rust, that is for sure. Especially the Coupes have problems with the rear window frame. There are several W 210 an W 202, which have rust problems, especially on the upper door frames.

Big rust you will find on all W 123 (even the younger ones, if not taken care off, for example the area where the hood hinges are attached), of course the W 115 and especially the W 116.

Biggest ruster of all is the R/C 107. They are really bad.

Pretty much on all models you will find rust either at the window frames and/or behind the inner wheel house behind the front wheels. This area needs to be flushed with every car wash.

On my W 110, which spent its whole live on Long Island, there is rust everywhere.

I kind of like this area:

It is all original rust. Original rust you take the original body panel and replace the whole area to get a decent result.

A little tricky is the C-pillow at the fintail-body. It will be some serious overhead welding to get that area solid again...

Kind regards
Eberhard