Somewhere on the Shoreline of Connecticut there is a green 68 convertible RS/SS that lost its cowl tag in a firewall repair accident.
At the show where I saw it the owner had a history board of the restoration the car had been through.
His shinny replacement cowl tag was catching the sunlight so it was a hot topic even then in the early 90's. The owner had tons of photos of the original tag and could have had a GM style reproduction made but he knew that would always be suspect of his numbers matching girl, so he had one made of brass like a ships dedication plate so there would be no question it was not original.
The replacement tag stated that in this place once was mounted the original Fisher Body trim tag, This plaque was made to commemorate the original that was damaged in a repair and stated the date on which the original had died. It then listed all the information from the photos. He also had the POP in his fathers name to back up everything. Always liked that as the perfect way to replace and honor a lost tag.
Would that solution also work for you? In your case only list what you can prove, such as the year, and the model style, maybe the plant if you can prove that and leave the body sequence out, document the exterior and interior colors and maybe the build month if you can prove that by other means, but if not just state the facts, this is a replacement tag as the original was lost or stolen. Make it proud metal and call it done.
Just MHO
