Flat Black on Trim - 68 Camaro RS

[Johnjan]

Debating how to apply the flat (or satin) black on the aluminum grill surrounds, headlight surrounds, and tail lights on my '68 RS.

Conventional wisdom says epoxy prime then apply the black but I'm afraid of building up too much thickness since these are just painted areas on metal trim. The "edges" of the paint will be visible. The original parts are very usable, I don't want to replace them when I can mask and respray the black.

Can I just scuff and clean the areas and paint? Without primer? The factory black finish on these parts is very thin.

Suggestions?