Do you have a link to that one? I want one like that. All the one's I've seen are angled like the 03-07 (classic) chevy's.
I don't know why but Westin doesn't have actual product pictures of the gmt400 version, they just have gmt800 pictures. Even for the our version but this is it: http://www.summitracing.com/parts/wsa-40-0085/applications
Just look for the part number 40-0085 from whatever website that has it cheapest and that's what you want.