The rear seat metal riser ( the area just behind your heel if you were seated in the back seat of the car ) would have a series of small screw holes. I think there was about 12 screw holes used to hold the carpet in place against the vertical riser. Carpet was found in the Deluxe sedans only. You might check with Rick Black, the MAFCA webmaster. He has written several articles on the 31 Deluxe Tudor sedans.
If we're talking tudor. It has a wider driver's seat with slide, dome light, rear arm rests, window shade, grab straps on the rear pillars, cowl lights, wood grained window mldgs and dash, dash is pin striped.
Paul in CT
Vendors have a book dedicated to the tudor. Very informative.
I reserve the right to be wrong, but I am thinking that the front bucket seats are the same as those in the Victoria, the 400A, and the deluxe phaeton. And as also mentioned, cowl lights, wood graining, and pin striping on the gas tank are other distinquishing characteristics.
Original deluxe tudors had a small clip riveted to the metal panel where the rear arm rests were attached. Sorry I don't have a photo, and my memory doesn't allow me to describe this any better. Of course you could only see this if the arm rest, and perhaps the upholstered panel, are removed.