[Keith Seymore]

The only markings on the firewall on my car are a large "A-A" in the center of the firewall, and a small "ok" under the voltage regulator.

There is also a small ink stamp on the cowl side that says "Elect Test ok".

Normally if you see any digits they will relate to other option content, or (more likely) to the final line build sequence number. Theoretically those should appear on any component that was prepped off line and then conveyed to the main line in sequence (rear axle pumpkin, inside one wheel, front of dash, radiator support, grille, inside the hood, inside the fenders, inside or under the seats, etc. Those were all clearly marked on my pickup truck, for example).

K