just my .02
If you like the pipe, go with it. Perfection is nice, but.....
I have several pipes where the drilling is not "perfect", but the pipes still smoke fine. I have a peterson spigot that is ever so slightly off to the side of center, but I have no problems. I have Savinelli that is centered, but about 3/16ths above the bottom of the chamber. Smokes well, but cannot smoke to the bottom of the bowl, but close enough for me. I have another Peterson that the stem drilling is a bit off center. Again, I do not notice any real issue. It smokes fine.
On the other hand, I have a vintage comoy's that is drilled perfectly that gurgles. I personally think the drilling is "close enough" works.
For what its worth, an imperfect drilling on Peterson's seems to be a bit of the norm.
jojoc