The original tire sizing was usually scribbled on the upper right side of the deck lid. I have documented yellow, black and white and it appears to be done with an oil based marking stick. I've also noticed that the car's color might be what made the difference in what color marking was applied. I have many photos of original markings from various 71 Chargers in different colors with different tire sizes. Let me know what color your car was and the approximate build date. I might have a photo of a similar car. I've never found any other markings in the trunk area.