The bumper mounts with either buck downs or rivets on the outside of the tunnel and yes the snow flap mounts to the bumper itself. The tabs that stick out are to cover the holes left in the IQ tunnel after you remove the stock bumper and huge tail light.
I have installed on my sled and it looks great.
Do an advanced search on my screen name and you will find some photos of it, they won't let me repost them again on this thread.