The parts catalog that I've just had a look on show this about Comet:
RRC000930MCM [ 8J X 18 - Bright/Silver - Comet ]
So looks like they are just a Bright Silver, rather than a 'Sparkle' finish.
Interested to see how they come out, and also how much it costs to get them refurbished... I've got Comets on mine, and a couple are starting to look a bit flaky in places, so it's on the list at some point!