Help me with Longines 12.68z stop second

Good afternoon everyone, I received this 12.68 stop second longines as a gift from my grandfather, but the chrono part is completely missing, any help is welcome, does anyone know where I can get pieces or any movement to remove pieces so I can complete this one. longines.
already grateful

You are missing some rare parts to say the least. Maybe a donor watch would
be the best option. Good luck👍

There is a lot missing on the watch, the movement parts, the original hands and the watch is redialed on top. Might be a difficult task to get
the watch in a satisfying condition. The movement itself looks in a bad condition.