Hi Glass,
I see your point.
Since the NR does not specify a coating specifically, I took it to mean that the outer layers of the diamonds had a coloration. Whereas a coating implies (at least to my mind) that it is a foreign material on the surface of the diamond.
I guess that we'll soon know more about this, if they find more diamonds of this nature in the re-processed SRC batch.
Lots of questions remain unanswered, but I have a feeling that at least some of them will be addressed in the coming week or so.
Good luck...peterjr