I have a suspision that Raven Blue is restricted to the Dune and the GT.
It's one of VW's "premium" colours, last (and still) seen on the Lupo GTi.
It's a very nice colour:

Looks a bit darker in real life.
Also, in the above pic, you might notice a couple of variations for the UK market - body coloured door handles and wing mirrors. Although the rear view mirror looks dark (ala Lupo GTi, I think it's just in the shadow). Unfortunately, I can't make out the seat coverings from this image (or it's hi-res original) - they just look "dark".
Deek.