It was my understanding that the color designated the inspector's ID, not day or night shift. L. Price was involved in the QC processes back then at Norwood.
Could well be. The final buyoff inspector on the Fisher side had a paper punch with an initial or number that he used on the body's inspection ticket (which tied his ID to that particular body), and he then stamped the firewall to show that the body had passed inspection. The individual inspection tickets with the inspection and repair punches were kept for 30 days, then trashed.
Chevrolet did the same thing on their side - inspectors had punches with initials or unique symbols to ID them, and repairmen had punches with numbers; when zone inspections were complete at the end of the line, the completed tickets were pulled, and the final inspector punched a 1" x 1" square adhesive tag and stuck it on the inside of the windshield to indicate final buyoff for that zone. A completed car ready to ship would have four stickers - "M" for mechanical, "P" for paint, "B" for body, and "RT" for roll-test. If you look closely at the photo below (early 60's Chevy II at Willow Run), you can see the stickers inside the windshield.