The right side of the notch for the extractor in the receiver lines up exactly with the right side of the notch in the barrel.  But the left side of the notch in the receiver is slightly to the right of the left side of the notch in the barrel.  I can feel the "step" when I use a bent paper clip.

In other words, the barrel could be VERY slightly torqued in too far.

Should I look for a witness mark somewhere that will verify the barrel isn't quite clocked right?