You only need to order these if the boot / bumpstops on your car are missing or worn out.
Normaly, your original boot / bumpstops are simply reused. But you do have to remove them while changing out a unit, so while you are there already doing the work, it's easy to just slip the new parts on since you already have the car apart.
They are packaged together in one box. One boot, and one bumpstop.