the calipers are metal and the fiber disc is the "brake pad" so to speak.. in stock form there is nothing in the way of brake pad material attached to the metal pieces that clamp on to the disc so you are all good there.
to replace the brake disc just remove the slipper assembly and the 4 screws (two on top and two on bottom) from the front of the tranny case (although there is another way that might work in the next paragraph) that would allow the calipers to move for installation. you wont need to remove the tranny from the chassis to do it.
Other way would be to remove the slipper assembly then remove the disc hex from the shaft, this will give some wiggle room to work the old off and the new on there. dont force it the fiber disc is not fragile but with enough force it could warp or partially break,bend, whatever.