[Brian]

I first rebuilt my car in the 70's. Parts weren't as easily available as nowadays in the Internet era. We fixed what we had. Back then, the little triangular gussets under the tailites [35 Ford] were impossible to find. The ones I removed were rusty as...perforated, you could see through them. If I had've sandblasted them they would have disappeared!. I cleaned them up with a rotary wire brush best I could and painted them with copious layers of "Seakrome" primer, a red lead rich paint subsequently banned because it's so toxic! These little panels fit up under the rear guards and by virtue of their location, collect all manner of crap, holding it in place betwix the fender and themselves. A true rust trap if ever there was one.
I have done probably a gazillion miles in this old car, in all weather. Currently refreshing it, man it needs it! Anyway.... I've just refitted the rear guards, etc, including those same little panels. Didn't even paint them; merely used some water to wash the dirt off. They are still in the same condition as 40 plus years ago. Got me thinking....that old paint was outlawed because it contained red lead. This modern stuff contains Cyanide, far more toxic than lead, [which is a naturally occurring element], and I'll bet it would not have the same durability.