LDraw.org 2020-03 Parts Update Now Available

[Orion Pobursky]

Grey is the only spelling we should use. I was surprised by the long list of official parts using Gray.
Is there a reason why these might have not been corrected?

For self-consistency reasons I agree. The reason they probably haven't been flagged is that both spellings are correct. Grey is more common in UK/Commonwealth and Gray is more common in the US but they can used interchangeably.