All production 1969 Camaro standard & RS grilles had body color perimeter.
Production standard grilles were molded in an off-white material; the center was painted silver for black and non-SS cars. A note in an early P & A manual advises painting the ribs black for SS. The headlamp bezels were painted to match the ribs. An August 1971 P & A manual lists both grilles available in black and silver.
Probably painted at the source; body color done at the production plants. By the '80s, all grilles serviced by GMPD were molded in black. Many were left unpainted.