Interesting discovery while washing my 348....

Primer. My door sills, when I removed them for a carbon fiber replacement, also showed some flat red color.

 

The deal is that, the factory just painted the whole car red, or what ever color you car is, and then painted black over the bottom part.

 

FBS (aka FSB) speaks the truth. The black washed over the lower portion of the car after the glorious red was already applied.
BT

 

Some people wet sand the black off to expose the red. There is no clear coat over the red on the body of the 348 I have, so in theory it would be the same. Being that the paint is pretty thin, and the area gets very much road debris contact it would need to be repainted before too long anyway, I went ahead and just had the lower portions (re)painted red. Maybe someone who has done the wet sand approach could post a pic of how it looks after.

BT

 

Fatbillybob put some break cleaner on a rag and wiped off the black. Just make sure you have water handy when you get to the red, because the break cleaner will take that off too.