Yup. It think it's actually particularly interesting because the assumption has always been Viking Inspired - Predominantly Aryan in look.
But this is a planet long since settled by Man. Why wouldn't that include varying ethnicities?
Splodge raises an interesting point about Abhumans. Except, Abhumans aren't purely down to isolated evolution. There's one short story from Inferno! which particularly comes to mind - in short, genetic manipulation was used on one planet pre-Age of Strife to adapt to the conditions. I know they wound up with three legs (high gravity) and I keep thinking they had something like blue skin?
So Squats and Ogryns may very well be subject to the same. Not to mention the warping influence of Chaos.