The switch inside on the drivers side arm, only locks the passanger door. The main drivers door lock lever locks both passanger and drivers door. Odviousley the drivers side 'key' locks the passanger door aswell.
If your having an alarm fiited, the central door locking motor on the Skyline wont be compatable. They will have to fit a secondary door lock motor in order for it to work, and for it to activate the central door locking for the passanger door.