I'm talking about the pearl being flat, as was the OP. The gen pearl is not flat, it has a convex piece of glass or sapphire over the lume.
You may or may not be right about the height of the wall of the retainer. It's awful hard to tell about that in the picture but I can assure you Sead knows what they are supposed to look like and he's seeing it in person. Another picture certainly is in order to make sure.
The ceramic pearl has a very thin chrome ring which is fully filled by the pearl. This one obviously has the correct width of the ring same as the gen I pictured.