There were S/Ds with glass instead of panels. The tailgate is the give away. I would think that it could be modified to get a back seat in there. The floors are the same. Need to build up rear supports. Or sell it and have fun building another car.
Steve not sure what his plans are for the car now he sold the sedan delivery and found an old Willys PU gasser that he is building now. The glass front end off the sedan is on the truck replacing the steel tilt front that was on it. I posted the build picks so far on the pick up.