Pg. 23-02 Step 7: Deburred the F-1255-L&R Longerons. Pg. 23-03 Step 1: Machine Countersunk the nutplate rivet holes for the Roll Bar Attach Plates. Step 2: Riveted the nutplates to the Roll Bar Attach Plates. Pg. 23-04 Step 1: Separated and deburred the F-1203G-L&R Arm Rest Brackets.