It is a bug that got exploited somewhat. Shortly after beta a select number of people had a bug where none of the helmets would show a preview or at all. And somehow the Ogryn helemet and others were available on every class. So those that chose that helmet on a non-Ogryn that happened. And it will stay that way until they switch helmets, and it will be fixed.
Grimdark Helmet.
It was part of the big content after the beta 
lol this made my day.
WHAT?!?! You went over my Helmet?!?!