It is up to you, but I wouldn't worry about the case of the T5 at all. Aluminum oxidizes very rapidly and this makes painting sort of challenging (because of the layer it forms). However the interesting thing is this oxidation actually protects the metal. What happens is when it is exposed to oxygen, a hard layer of aluminum oxide forms and over time it can continue getting thicker...which keeps it from oxidizing any further. Unlike rust it normally does not change the appearance of the aluminum. Usually the oxide is grayish.
