No they have an additive to last longer. That is why they are a lighter color then the GM units. The UV rating is much higher. Richard explained to me that it is sort of a soup & how certain chemicals are more then others. The fronts & rears have this soup like difference. Even though they have the same chemical make up the soup is a little different.
The steel behind it is a little thicker gauge with an EDP coating. You will not get that flaking between the steel from rust like you do on the factory fillers.