Besides a car that’s painted gloss black, have you ever seen any Camaro part gloss black?
Whenever the restoration guides or judging manuals call out "(100%) gloss black", such as for a heater box cover or air cleaner lid it should be understood that paint chemistry in the 1960's did not produce the same super high gloss that's possible today from even single stage paints. At shows and judged events I've seen perfect, blindingly glossy black painted parts on restored-to-factory-original cars however that high gloss isn't how the paint would have appeared from the factory back then. For "full or 100% gloss black", IMO the range of +/-75%-80% of today's full gloss is more representative of 60's era full gloss.