A lot of high white pieds seem to get those spots as they age. All I have are low whites, so I don't know, but I've seen pictures of some in Kahl's collection that even have them in semi-ordered patterns, which are AWESOME.
And my herp vet was trying to convince me that he saw a whole family of high whites that had a sort of X-marks the spot pattern that appeared on their white patches. (I told him he was making it up, but I'm secretly hoping one will turn up at the Phoenix reptile show this year.)