I was under the impression that GW's 3 current pewter wizards were designed to be sort of vague-- the bearded one, for example, though painted as a Grey Wizard in the Empire book, could pass as an amethyst (skulls and staff), or amber wizard (wild hair and leather pouches) with no modification.
I have the same pewter wizard you called the Gold wizard, but I've seen him painted by GW as both a gold wizard and a bright wizard. His ornamentation backs up my theory-- said wizard has paired brooches of the star and crescent (symbols of the Celestial Order) as well as a key ring (part of the ceremonial regailia of the Bright Order). I'm pretty sure this is deliberately vague, to make it easier on everyone by not having to supply 8 wizards.
The basic outfit of the plastic Celestial mage is the same as the new pewter "gold" wizard (high collar, skull cap, etc), but I think he has the star and crescent or comet on his outfit somewhere. I believe the Gold Order's symbol is a spread-winged eagle.
My comments about the plastic guys, though, are based on memory-- already demonstrated by the fact that I remembered some of it wrong. For all I recall, this plastic wizard could have the "gold" molded onto his forehead-- all I know is that at the time I took a good long look and thought he'd make a perfect Celestial Wizard.