Slot the holes that mount to the bumper and you can resuse it. Thats what I did on my K5 and Sub. The second piece you get with the steering brace sandwiches between the frame and that little bracket then.
I can't remember if the instructions say to discard it or not, but I pretty well figured, why do anything but keep it? Its more of a bumper support than frame strengthening for the steering box I believe. But every bit helps.