Yep white, black and silver are the common colours. You then get the occasional red, and storm grey I think its called.
Seriously thinking about getting a whiteline rear ARB - you can get the unadjustable ones for around £110. Adjustable ones have 3 settings but the hardest setting is almost undrivable on the road so cannot see the point in paying an extra £50 to buy one that does pretty much the same thing and I will never adjust. Lots of owners rate them.