The hydraulic suspension was an option for that car. It is in the original sales brochure.
Just because it is not in the owner's manual does not mean it was not offered. My owner's manual has nothing in it about the rear sunshade but that was clearly an option on these cars as well. It does not even give a location of the switch or an indication of what it even looks like (I have been wondering about this for years - have never come across a 126 that had one).