yes... definitely do the one piece. I had that on my 84ta. I cable rigged the trunk lock to the interior so I did NOT have to have a key hole on the outside. Kinda reminds me now of the engine cover pull on the D, cause I used a hood release pull from a junk yard car.
I've only had 3rd gen TA's, never firebird body trims, so i've never really wanted to do a full KITT conversion, so really enjoying seeing this thread. Good luck! Oh, rip that shitty motor out and put some real balls in there But, until you get her looking good, it's a good "move the car here and there" motor.