Yeah okay, you're right. They did replace the textures with a blank texture and recolor it via code. I honestly thought that was not possible without the base model and judging by how other users complained about 'datablock usage', thought separate texture swaps was the reason.
Quartz made it as optimally as possible. (at least to my knowledge)
And now that Im looking at it, you could easily add more hats to it. As long as you can open DTS files to replace the textures to be blank.
If need be, I can re-export all my hair hats without textures for this.