Anodize is an aluminum oxide coating over the bare metal, the oxide can be dyed different colors before the pores are closed. If you remove the coating, more aluminum oxide will form. What is known as rust is just iron oxide in steel, same kind of concept. The anodize (aluminum oxide) is harder then the bare aluminum or the thin layer of aluminum oxide that will form under normal conditions. It will resist wear better with anodize. It does form a hard layer around a more ductile base metal, but I can't imagine it lends much to the overall integrity of the chassis. Then again, I don't have any experience in RC chassis design.