I'm not sure what your question is...are you trying to remove the vent window then?
That bolt at the bottom there in your picture is an adjustment screw. I have a 67 so yours might be a little different mine, however on the door panel side you should have access to the head of that bolt. It might have an allen head with a hex lock nut around it. It should screw right out, and the vent window will lift up out of place.