Not true from what I understand - The HGW is a single co-dominant gene that just happens to look like a Woma. And since they were given a crappy name (HGW) people get confused and thing there really is a hidden gene. In the beginning it was thought there was a hidden gene but then later found it's just a different gene altogether, not related to the Woma. It should be Type I and Type II Woma (which I've seen a few people adopt, thankfully.)
The Pearl is the super-form of the HGW (or Type II

) Womas don't have a (visible) super, they are dominant.
I don't know anything about Kevin's HG Lesser's, but he's even guessed (in his ads) it might be the same thing as the Platty gene. So who knows on that front for now