I'll go out on a limb here and say they may be damn close to the same color. That the difference could simply be metal flake. It's been a while since I looked at a 69 Coronet color chart (had one) . But I don't recall many being metal flake. Run of the mill cars just didn't. I'm thinking it's possible that 1970 and cars, like the Challenger was about the beginning of their common factory use outside of a limited number of colors. Someone will know...
Yep depends on car and lighting
Yeah, I will have to check. He actually built a '33 Ford coupe and did it in the "same color"....but the 33 has metallic but I not sure about the Coronet tbh. Painted himself (used to be a body man). Built a booth in his garage and piece by piece..... Was funny seeing doors, trunk lid, hood, side panels, fenders, and running boards take over the living room after finishing each one.
Amazing how a car without orange peel just....pops. That said, like you mention lighting, went to Barrett Jackson and was blown away with how some of those cars actually look like absolute **** in person when they parked off-stage for up-close viewing. Then when watching the show when we get back home and they are on stage.....you would never guess they were the same car.