I found the answer to my own question from a buddy who works in a paint shop. He used a rag with some compound and was able to get a deep gloss from the yellow that was like the topside body color gloss. Cool idea! The red primer area he rubbed had a slight shine but nowhere like the gloss as the yellow. He did this to show me the difference between the two to rule out the yellow being a form of primer. He said it was likely darker because of the red oxide primer under it vs. the gray primer used on the topside and the fact that is was mainly thick overspray even though the whole under carriage is yellow over red oxide primer right up into the tunnel and stops at the floor meets cowl line. I still donít know how a reciprocating sprayer would reach so far under unless the fan size was very large, and seeing other examples of the same coverage on other posts, I'll go with what I found.
So, if the results donít follow the theory, keep the results and change the theory.
So this is how Iíll restore the underside