From ATE catalog;
Atleast in Fiat Croma 2500 D and 2000 i.e. so propably its in all early Cromas
24.2122-0802.3 Master Cylinder, brakes
Trade Numbers: 010374
?: 22,2 mm, Number of ports: 4, Thread Size: M10x1, Length 1: 18,8 mm, Length 2: 167 mm, MAPP code available

Remember that the integral shaft in ATE master cylinders, the pipe kind of thing coming from the cylinder, where you pedal pressing bar is pointed at, CANNOT BE SHORTENEDE!!!! It is contact surface for seals, if you shorten it, it will leak when pressed.... Its possible to shorten it a bit, but not much. I have this kind of cylinder in my track BMW and I shortened it....

And it leaked

This croma master cylinder looks pretty much the same as 131 cylinder.
It seems I could get new for 80?, or seal set for 20? but the supplier I use is sold out at the moment. I think its easy to find it from Poland also.
Marko