Good idea Scott. I believe if the information on the codes rolls in, I will develop a spreadsheet documenting and cross-referencing them.
I have been able to pretty well decifer the Billing records codes since I have my original window sticker and have owed my 68 since 69. I will go though the PHS documentation and identify any codes they don't explain.
There are also a number of codes on the Body Broadcast Sheets that some are lucky enough to find stashed around the cars. I have a couple mystery codes on mine but I'll try to decode them from known equipment.