Hey fellas, ease up. He has a burb that came with two seats and a rear cargo area. In that config, the second seat could correctly be called his back seat. When adding a third seat, his former second seat (full width) should move to the rear and a proper (narrower) second seat from a true three-seater should go in the middle. No further fleshing of thoughts is necessary here, unless you are asking someone that is unfamiliar with suburbans.
As for the glass, two-seaters had one set of sliders forward and one fixed window in the far rear on each side. Those equipped with three seats had two sets of sliders per side.
Though I've never done it, I'm guessing it's pretty straightforward to swap them out. finding the parts should be the only real hard part. look for a donor that you can pull them out of and educate yourself in the process. Good luck.
