I've noticed that too, but from the Illusion days forward. In the early days you see him picking near the bridge, which is probably more of the Appetite sound.One thing I've always noticed about his playing style is that he tends to pick near closer to where the neck meets the body. That gives the tone more of that Duff "dirt clank" that is always present. Picking close to the bridge makes the sound more "tight" which I personally don't hear in his tone.
A++ to the GK 800RB