good pic Ron,,,, I'm in storage, but might go out next week will drive around if I do..... Ok I can see the gutter rail where the cap is going to be set,,, want they have to fix some support at the cut area and where the liner and shelving goes? I can imagine the cap being placed on the cab, liner in place maybe some caulking, then screwing it down like some of the guys have mentioned. Wonder how hard to take the bottom of the two cabinets or Tv cabinet out? Maybe you could see the screw line where they attached the cap. Hate for you have to take out that headliner ouch what a job,,,,,, Might want to call the PC factory get some suggestions... good luck and be carful around that metal edge
sparky