I've actually wondered and reaserched this thoroughly, and from what I can tell, the "defect" is on one of the kings, the boarder is larger on one side, but it's hardly noticeable according to reviewers.
Suposibly David did this on purpose, but then ended up deciding he didn't like the way it looked.
There's really nothing wrong with them and I'd doubt you, or anyone else would notice unless you were specifically looking for it.
Personally I don't like the look of the black lions, I much prefer the white lions, but that's just a beauty is in the eye of the beholder situation.
Either way I hope this helped! Trust me, I've been exactly where you are and it wasn't easy to get a straight answer about what it was.♤