There's so many variations between years, plants, running changes, and operator preferences, that its impossible to have one perfect guide to every detail. Fitting everything in a 40 page judging "guide" means you're skipping a lot of details, and making generalizations about others. We're dealing with 40 plus year old cars, that were all built differently. Each year, we learn more, and if we can nail issues down, the understanding changes. A while ago, the standard was that the underside was to be red oxide, come to learn that in '70 ('69?), the Dearborn plant used slop paint, and so red primer wasn't correct for those cars. Hardware differences, paint markings, etc., had a lot of variations, and the only thing we can honestly expect is that as time goes on, we'll find more things that we had wrong. One issue still out there is the understanding that the convertible pads should all be made of canvas, when in '69 and '70 they went to a short nap carpet kind of material. Hopefully, over time more judges will learn this detail . . . If you think that's a small detail, how about what carpet is correct for different '69s and '70s? (Heel pad, toe pad, nap, stripes, etc.)
Keep the faith, all we're doing is improving our understanding, whether the underside is red oxide or the auto tranny filler tubes are color coded. And rather than sanding the black off, I gotta say a bead blaster is a real nice tool to have. :^)
Carl