"Z28" is an RPO code for performance and a popular option for Chevy Camaros from 1967 to 1974, 1976 to 1988, 1988 to 1990 (IROC) and 1991 to 2002, according to Chevy-Camaro.com. Automatic transmission was not available on the first generation Z28.
Starting in 1987, the Z28 convertible could be ordered by a person other than a GM executive. GM did not actually build the Z28 convertible; instead, it was built by Automobile Specialty Company (ASC). The Z28 convertible disappeared in 1993 but was available again from 1994 until 2002. The RS and SS, or Rally Sport and Super Sport Camaro models, were also discontinued in 2002.