If you are at the rear , lay down , look at the rear axle , and approx. 6"?or so out from the left end/brakes and facing straight to the rear you should see a stamping....approx. 1/4" in ht. it may be covered in dirt and or undercoating , you may want to scrub or use a steel brush... I dont remember the different codes ,but after you find it you can ask....someone will know..
