To clarify:
The #4 body mount is the one behind the rear wheel; the frame VIN is centered on the front edge of that bracket, on the top surface of the frame. Pull the rear wheel and clean the top of the frame and you should be able to see it with a small mirror.
The second location is about 12" forward of the #3 body mount (the one between the door and the rear wheel opening), but this one can't be seen with the body on.