That looks to be a 64 basic wagon. I have a 65 by my shop and I am 99% sure that it does not have a GS rear end under it. The Sport Wagon with the windows in the roof is a heavier car and has the GS style rear end. The Sport Wagon has the boxed frame, but is five inches longer than the GS frame. The best part of that car looks to be the grille and maybe the back window if it doesn't have a streak down the middle of the glass like most of them do. The rear window fits all the A body wagons without the roof windows. The rear quarter panel on the passenger side would be interesting if, by any chance, it isn't rusted and dented (highly unlikely).