[SS427]

In addition to Tom's comment, many Chevelle plants put the color code in yellow crayon just behind the brake booster and the schedule number in the recessed area behind the distributor. These have always been on the bare metal before the firewall was painted. I sometimes find remnants of masking tape on the top side of the firewall in the center where a build sheet was taped during assembly and ripped off.

On a recent Deuce restoration, I found what appeared to be an "A48 or 448" in the recessed area of the firewall. As I had no build sheet, I could not dicifer what this number meant. Marlin, I believe I sent you photos of this.