I found the pictures of the survivor, Norwood 03D build, '69 Pace Car that I mentioned earlier. I included for reference a view of the trim tag along with the blackout on an RS headlight door cover.
As firstgenaddict suggested, it appears the covers were placed in a slotted fixture for color painting. When you study the pictures, you see evidence of a straight line on the tabs between the color and blackout.
Would like to see pictures of the original screws used to attach the cover to the frame to see if they were silver CAD plated or gray/black phosphate plated.