I went through this with PCNA last year, trying to get my COA corrected. I finally had to point them to the paint color codes page on this site (
here) to finally get them to agree that "26" (what was in their records) is not the same as "26G", which is what they put on the COA. BTW, "26" is Saturn Yellow and equates to L13M, which is what is stamped on my tag. "26G", on the other hand, is Conda Green, and wasn't even available on a '73.
It took a while, but they finally apologized and sent me a corrected COA. Unfortunately, there isn't much info on the COA besides color and engine serial -- no trans serial, MSRP or even options listed.