Help with duster 1/4 windows

Yes, been there, done that. There should be some foam weatherstrip around the upper perimeter of the frame. Are you saying that when you have the window in place - up as high as possible with the little L-shaped mounting bracket against the roof rail, and the lower corner mount lined up at the jamb, and the rear mount lined up with the hole in the body inside you still have a gap at the top? Did you remove the chrome roof rail weatherstrip channel and, if so, replace the foam seal between it and the body upon installation?

Can you supply pics?

If anything you will have a gap at the lower edge of the window frame and body that you'll have to fill with a strip of black window caulk.