Is there a way to change the color/ texture of bodygroup pieces in Gmod?

I have a ragdoll that has a bodygroup piece that is silver (with a shiny reflecting texture) on some maps but normal-colored on others.

How can I change a bodygroup to be a different color?

Thanks

I do believe pac3 is capable of that

Im sorry, is that an addon for Gmod? What would I have to do to get it?

For tutorials http://lmgtfy.com/?iie=1&q=PAC3+Tutorials