We discussed this topic on Moparts also. If the car was built at the L.A. plant it had a black dip where other plants used a grey dip(primer). Looking at the pics of my car where the gas tank was mounted. You can see it was black (plus the VIN tells me it was built at the L.A. plant). So I am thinking about going back to semi gloss black on the under carriage. Still not 100% sure but that is the way I am leaning.