Looking at the pics, my opinion is that the milled lines on the frame are off slightly. The rear sight and barrel shroud lines line up fine. Cosmetic, but still an issue if it bothers you.

If you are concerned the barrel may be screwed into the frame slightly cockeyed, I would try measuring the cylinder gap on both sides and see if it is the same. Should be, otherwise the barrel isn't screwed in straight, or the face of the forcing cone is un-even. That's assuming the cylinder and frame is straight....

Larry