Morse Twin S controls

[The Nauti Dog]

Attached are photos of the controls. Does anyone know if the neutral detent plate is internal? Neutral is tough to find occasionally. Believe the bottom screw is a tensioner and a top one was a screw with a ball and spring as the detent screw. Not 100%. Boat bought late last year and is missing a screw or 2 on the housings. They operate decent and are very smooth