I started re-watching Season 1 recently, and I noticed that Locke wore a brown shirt through most of the season. (No no, don't hang up. This is going somewhere. I'm serious.
Then, after his first encounter with Smokey (when we don't actually see the monster) he returns to camp mysteriously calm and collected--and wearing a white shirt. See where I'm going? Well, some stuff came up and I wasn't able to keep watching the season. I ended up skipping ahead a bit and the next time I saw him he was back to his brown shirt. Then of course in S5, when he's secretly inhabited by the spirit of X, he's wearing a dark shirt again. (Black or brown, can't remember.)
I'm wondering if any of the eagle-eyed watchers out there can tell me if they noticed any pattern in Locke's shirt colors over the years. I'm wondering now if it's possible that he has a white shirt on when he's being inhabited/portrayed by Jacob, and a black or dark shirt (other than his original brown one) when he's being inhabited/portrayed by X.