I agree, it seems very unlikely that he would tout it as such without being reasonably sure. I guess it just seems like with alllll of the many genes being tossed around in NERD breedings nowadays, it would be tough to ever be sure 100% what was in an animal!
And also, what with all of the many many combinations that turn out to make a white snake ... Even kind of unexpected ones ...
I really have a tough time envisioning an extra mutation somewhere else "fixing" whatever it is that causes the severe neuro signs in the pearl ... I guess it's possible, but it's hard to picture. Also, I thought the whole "lesser pearl" thing was a rumor ..??