Locking The Rear Sliding Window
 

Hey everyone I just picked up a very ugly '80 4x4 hilux and I'm in the process of putting it back on the road. I'm at the point where I can start driving it around town and I want to fix the rear window so not everyone can open it at will. Right now there is nothing stopping it from sliding all the way open. The two halves clasp together but you can push them either way far enough to reach in.
The short term fix is to put a piece of brass on each side so the glass doesnt open at all in either direction but when summer rolls around and I want to have it open, what do i do? How were these things designed to work?

thanks in advance

Generally there was a central latch that kept the windows closed; you pushed down on one side of it to release it. Never heard of a lock for one, except for the good ol homemade standby. Got a piece of oak dowel rod whose width would fit into the inside slider tracks (measured this), cut the dowel rods 1 inch shorter in length than the length of the tracks, dropped dowel rods into tracks. Even if someone could get the latch undone from outside, the window would only open 2 inches max. With windows closed, the rods being 1 inch shorter than the track makes em easy to fish out from the inside with just a finger.

Supposed to have a STP between the windows that keeps them from sliding past the halfway mark.