I know there is a way to make a colorable bumper for a truck. I tried to make it but It doesnt work for some reason .....any tips???? If u know pls write down here It might be a good lesson for other people --- Post updated --- I saw @Taza made a colorable rollbar so I think it might possible for chrome Tseries bumper too!
You need to help yourself at least some of the time. The Pickup has both chrome and body-colored front bumpers. Compare the materials for each bumper and you'll see the difference.
Did you review this? https://wiki.beamng.com/Introduction_to_skin_system#Colorable_Skins_.28Advanced.29