The Bandiera livery was introduced in the mid-1970s as FS started repainting the TEE Coaches into coaches for domestic traffic. In international traffic, the newly delivered "Eurofima" coaches replaced the TEE coaches. As the TEE fleet had been exclusively first class, FS ordered a number of Eurofima inspired second class coaches, to be painted in the bandiera livery, with the difference that the second class coaches had a blue instead of red stripe.
I have seen some of the UIC-Z coaches in bandiera livery in trains in Switzerland and likely into Germany. I don't think that the older Gran Comfort (ex-TEE) coaches continued to run outside of Italy, as those coaches required the use of a generator coach to provide lights and power (heating).
So, if you are modelling Switzerland, Austria or Germany, you should limit yourself to FS TEE coaches with generator car or to FS UIC Z coaches (Eurofima, VSE derivative coaches) in C1 (Orange), Bandiera (Bz), Bigrigio (Az, Bz, etc) or XMPR. (Green/Offwhite)