No, here in Brazil we don´t have Monzas like Opel Monza. Our Monza are just the Opel Ascona C and a face-lift did in 1991, like Marcelo's car.
GM Car-line-up in Brasil in 80's:
Opel Kadett C (sold in Germany from 1973 to 1980) - Chevrolet Chevette (sold in Brazil from 1973 to 1993)
Opel Kadett E (sold in Germany from 1984 to 1990) - Cheverolet Kadett (sold in Brazil from 1988 to 1998)
Opel Ascona C (sold in Germany from 1981 to 1988) - Chevrolet Monza (sold in Brazil from 1982 to 1996)
Opel Rekord C (sold in Germany from 1966 to 1972) - Chevrolet Opala (sold in Brazil from 1968 to 1992)
Opel Commodore A (sold in Germany from 1967 to 1972) - Chevrolet Comodoro and Chevrolet Diplomata (sold in Brazil from 1976 to 1992)
AsciFan, I think this tail lights are easy to find and import from eBay UK, those are the same from Vauxhall Cavalier MK2 SRi.
For people from Brazil: Opel Monza is a car bigger than Brazilian Monza, in fact is like a Opala Coupe evolution with the 3liters engine used in the Brazilian Omega.