Is there a factory undercoating GM does from the plant? If not, are all axles, frames and underbodies painted the same? Heres why I ask... now that I have a truck, I have noticed that some trucks have black undersides and others have orange rusty ones. Guess what? Mines is orange. only 3 winters old and is already orange everywhere. Salt? Yes I'm in Minnesota. But sometimes I see Silverados that are the OBS maybe 2000 model yr. that are still black. p.s. usually Phords are pure black still... Any input?