The concept art predates the screenshot, it was just shown later (they have to, you know, design the jumpsuit before creating it in game), plus, the face shown in the concept art can easily be created with the Fallout 3 facegen, and in fact, was probably took from it.
But, so what if the concept art predates the screenshot?
I'm sure they had a lot to work on so by the time they decided to show raul they hadn't completed his appearance and showed his placeholder instead.
They surely had concept art for the super mutants as well and we've seen how they've been redesigned but even so we still got screenshots with placeholders in 'em.
Could be the same with Raul.
Until they release a new screenshot of him it's entirely possible for the first screenshot to be either placeholder or final cut.