As far as I know, this bodyshell was used by Fiat for 1800, 2100, and 2300 cars, and 1500s. There were also some stretches made largely by Francis Lombardi.
Seat also used this bodyshell for 1400 and 1500 models. The cars with the chrome strip above the windscreen and windows were the top of the range versions of the six cylinder cars. Confusingly, one of them, the 1800 Speciale, was produced with the 2100 engine, but the later model, the 2300 was produced in 3 luxury versions - all with the chrome strip! They were the Lusso, the Speciale and the President. It's not the Lusso, so is it the Speciale - which had a slightly longer wheelbase?