Underside floor paint on a '67 Camaro

[Too Many Projects]

I've been cleaning the underside to get it ready for paint and am convinced this paint was applied by the factory. Too much evidence to ignore.
Does anyone have information or experience with this on a LOS built '67 Camaro, or, possibly, other models built there ???


Blue under the axle bump stop, I believe I am the first person to remove. Gold overspray on top of the blue.





Runs of blue in the left torque box with gold overspray on top.





Inside the shackle bushing tube. Bushings are original.







Under the original undercoating near the left rear wheel well.