John,
There is no source for most this, just information gained from disassembling the original cars. The assembly manual will provide the color of the markings on the front and rear springs and the shocks and maybe the driveshaft markings. As for the firewall markings these vary from vehicle to vehicle depending on the options on the car. About the only thing that you will constantly find on the firewall is the interior code. I attached some photos of the firewall in my 61SS that were taken prior to restoration, while these will not match yours perhaps it will give you an idea of what may have been on yours. You can see the 841 (interior code) and the 4 speed markings that were on mine.