Needle is not illuminated by LED, and it's color is determined simply by the underside of the transparant plastic from the needle. Scrape off the red and give it any color you want with a bit of paint and you're done. No soldering involved. It's simply a matter of taking off the needles and repaint that underside.
Combination of both it seems, scrape the paint and optionally change the LED: http://ozvr4.com/forums/showthread.php?10580-How-to-Illuminate-your-dash-in-a-different-colour