Did a little research for Austian police T3's, but few I can find, actually I found only one real life image.
I think the one in the set of Schuco vehicles matches the best. Do we want the "Gendarmerie" on the front and "Polizei" on the side or is that actually not realistic?
The red on the Golf image is correct I assume.
Not realistic. "Gendarmerie" was in the 90s the countryside police and the "Polizei" was only in bigger Cities (Vienna,Linz,....)
Gendarmerie was red, with red "GENDARMERIE" and Polizei was orange, with black "POLIZEI"