The 155s are the small wheel version of the 195 and share most of the same components. Since they were only made for a few years, 40 years ago, they aren't as plentiful as the 200/400 series models but they are not really rare. The hydraulic lift was an option that was not sold on many tractors so that is somewhat rarer.
I don't know what model tractor you are thinking of installing the sleeve hitch on but it won't fit any of the 200/400 models or later. It may fit on a 195 but if I had a 195 and just wanted a hydraulic lift I would move the hydraulics to the 195.
The asking price seems a bit high but it all depends on the condition of the tractor. These are mostly collectors items these days so something that is banged up and missing parts would be less valuable than one that is straight and solid.
I don't know what model tractor you are thinking of installing the sleeve hitch on but it won't fit any of the 200/400 models or later. It may fit on a 195 but if I had a 195 and just wanted a hydraulic lift I would move the hydraulics to the 195.
The asking price seems a bit high but it all depends on the condition of the tractor. These are mostly collectors items these days so something that is banged up and missing parts would be less valuable than one that is straight and solid.