None of the underbody colors were truly "Flat", all had a dull sheen to them, just nothing like the paint did. The factory dipped the cars in a rust prohibitive sealer/primer bath up to about the armrest pad level, then the cars were baked in an oven which hardened drips you see on the bottom contours of the floor pans and caused the thick hardened bubbly residue inside the cars trunk floor and interior floor pan areas. The cars were then shot with primer and paint and baked again. The dip coating they received was a medium elephant grey color for most plants, the Los Angeles plant used a much darker colored material that was close to black but was actually a very dark bluish grey. The duster example shown here shows the proper Los Angeles dip primer color, before and after restroation.