The Stovebolt Site Forums The Shop Area General Truck Talk Firewall chalk/crayon marking

...and a recent article by an assembly line worker from the later fifties said sometimes it was the previous workers initial signifying his job was done.....in one case the markings were under the fender on the inner fender and to keep from bending over they would hold a mirror under the fender to see it.
Many have reported that some marking also indicate trim, engine and so on, or other options as it went down the line.....and that it may vary from plant to plant.