I have wondered the same thing with my 4100. Like yours, the inner tubes in my emulsion tubes are not installed in the center of the tube, though mine are not laying directly against the wall of the outer tube covering any of the little holes on the side either.
It is one of those things that make me wonder if it was intentionally offset because that is how the booster is calibrated or if it is out of alignment because it just does not matter or of it was just lackadaisically assembled/installed. There are soo many "little" things about these carbs I would love to know better about this being one of them.
It would be interesting to know the general consensus regarding this from other people too. Are all of them off center or do some people have boosters with them installed directly in the middle? Does it really matter where they are? I'd love to know.