This is just a shot in the dark, I have not tried this nor is there any guarantee that it would/could work.
I think the TG3 and the Déck caps are both made the same way, essentially it's a double shot where the whole inner part is white while the outer part is black. Don't quote me on this but I think I read somewhere that SP makes these.
At this stage they look just like we would like them, black with a semi translucent white top.
These are then dye sublimated with a black dye to form the letters & symbols on top, now the dye will penetrate into the plastic and permanently stain it, the only question is how far it penetrates.
It might be possible to sand the dyed plastic off the top, depends on how far the stain penetrates, like I said it's a shot in the dark.
Ideally we could just arrange a group buy for the caps without the dye but I suppose TG3 and/or Déck have some sort of patent or own the molds which would prevent us from dealing directly with SP or whoever makes these, might be possible to strike up a deal with TG3 directly though if someone is up for negotiating.