Gentlemen, that change of color and texture in the outer wheel well photo is simply showing old caked on dirt, and the clean painted area is where rain water sprayed off the tire keeping that area cleaner. I’ve seen it many times.
What a wonderfully preserved time capsule of a ‘67 1600! Hopefully the next owner understands how unusually rare it is as it is, and doesn’t do a thing with it but preserve its originality. No restoration needed with this one, perhaps just a sympathetic cleaning and detail.