they are supposed to be offset a little bit,
if you look at the, receiver from the rear angle, youll see the front ring is actually offset just a tad, and the reason the new made bases dont fit worth a crap, the early and original bases were made with this in mind, and made off set, so that they would fit on the rifle correctly with no large gap.
look at a real A4 with the base installed, it will set just like the one you have, your hole is drilled correctly.