Check out this link which shows the riser plate, also known as the T-Plate:
In that second set of photos that you posted, it looks like there is no Riser T-Plate on that ski. Yes you do have to mount that metal piece that rests on the orange colored piece for the heel. The reason for the confusion is because on your bindings, they made the mountings orange to match the ski. Usually when you buy the binding at retail, that piece is all black.