The vin should be stamped somewhere near the drivers side speaker hole regardless of having fold down seat or not, you'll have to remove the cardboard package tray cover to see the number, it's usually not deep enough to see from underneath. Your probably going to come across a number/letter combo that is embossed into the panel, this is just a part number used for that piece of sheet metal as the body is being assembled. The VIN stamping wont have raised letters/numbers.