Hmm, I dont think so. I mean if you look at his highschool pic (once you get past how BAD his hair is in the pic) you can kind of see that he always had that sort of "look".
I know that Gackt had some sort of surgery on his forehead(i think...?) because of a nasty cut, so yes, he has had a little bit done, but if it goes beyond that, I dont know. And he still looks like himself in that high-school picture, just more like someone you would expect to meet walking down the street, someone you wouldn't really look twice at.