Getting close to finishing restoration on a 1968 cuda BB. The side rocker pinch welds are body color. The factory didn't have time to do any detail work. This would be different on cars that had the shark gill rocker moulding, as these had argent paint added. The frame rails you are referring to (by front suspension) is a little more complicated. The factory did not specifically paint anything under the car. When you see paint under the car, this is mostly over-spray. Results were very random determined by how hung-over the employee was. 50 years later, it is better to just have fun with your car and leave these issues to restorers who like to debate these issues.
