I am not saying the leather is part of the Winter Pak, but I will also say that if they came with MB Tex, I have never seen one ..every one I worked on had leather..might be a Euro/MB tex thing ?
I have also been told that 94/95 -124s/US came with the leather option, regardless of if being ordered or not...but that is just an observation..
The memory seats is a rare feature, but the heated seats are common.
Regardless, you will like that chassis , for sure...and there are many Techs here familiar with that chassis, and many DIYer threads on most problems are in the Archieves.
The first 124 chassis with decent lighting, by the way........and you will enjoy the first gear start and a cruisin' rear differential ratio these had over earlier 124s........