My door locking mechanism is a three point lock (top, middle, bottom). The lock is actuated when the door is closed and inside the top, there is a trigger that is pushed in and causes a locking bar to slide down over three lock studs. The only number I can find on the unit is manufacture date of May 1995. I'll try to attach a few pictures. Looks lke I can only attach one picture. This the door handle and the middle lockwhere the sliding lock bar is located.