I seem to recall it was the same color as the 70-200 II. I brought it out after several weeks and they look very different. Do Canon's white lenses change color like mature cherrywood in the sun (just not that gracefully)?
The white changes colour, I recently commented on this same phenomena as my ten year old 70-200 f2.8 IS and practically unused tripod ring it came with are completely different colours, yet they started out identical.
There are at least two original whites too, the MkII superteles and the MkIII TC's are a different colour to the older stuff, but they all change colour quickly with use.
The 70-200/2.8L IS II is 'old white'. I think it was the last lens to use the old paint. The MkII superteles, MkIII extenders, and the 70-300L are 'new white'.