There was no injected version of the 131, apart of diesel
Well, strictly speaking that's true but the USA version of the 131 Mirafiori which was known as the Brava had versions with fuel injection
But also some of the works rally 131 cars had kugelfischer mechanical fuel injection although it was never fitted to the road going Stradale versions; they simply had a single twin choke carb.
But when I mentioned emission equipment I didn't mean fitted to injection engines. Some 131 engines had vacuum operated air valves that would introduce clean air into the exhaust ports; a system also used in the first series Gammas and possibly other Lancias. Emissions are measured as percentage of the bad stuff in the exhaust gasses so if you add plenty of fresh air in the exhaust the percentage of the bad stuff is considerably less
Here's a 131 engine with such equipment fitted.