If a possible thesis of the Riviera Project is that exterior design matters, then by definition, the exterior colors matter. A detailed study of these colors turns out (surprise!) to be another rabbit hole.
I have decided to build visualizations of each generation’s colors, trying to get all the years and colors on a single page (though that may be challenging with the lengthy sixth and seventh generations). Building accurate visualizations means some attention to detail: the same color name may change painting codes from year to year, while the same painting code sometimes applies to different color names.

I’m using (mostly) scans of the original paint samples from PPG and others. These samples have, of course, aged—and accurately restoring them is non-trivial. There’s also the whole issue of how to depict different textures of paints—metallics, Firemists, etc.—one I have not yet solved.
There are many reasonable ways to sort and display these colors. I have chosen to organize the colors in the traditional ROYGBIV fashion, with the blacks, grays, whites, and various beiges and browns on top. I also combine color names across multiple years if the paint code stayed the same.
Building the visualizations in this way clearly shows changes in color fashion detailed in The Secret Lives of Color and other books. For example, note the pronounced movement toward more beiges and greens as model years moved from 1966 to 1970 in the chart above. There were also no yellow second-generation Rivieras, though the prior and following generations both offered various yellows.
Thus, we proceed, with the one guarantee that the charts as currently designed are probably not in their final form.