Your friend could get under the rig and read the tag on the rearend. He could also jack up the back and spin the tires and rear end to get his answers.
This is not rocket science, if he can't handle this than the info would be a waste of time to him anyway IMO.
Same with lots of other posts, you'd be surprised what you can find out on your own by lifting the hood with a tape measure in your hands. You have to start somewhere, or the service/parts/shop guys will eat you alive and you'll never be able to get yourself back from an offroad excursion.
Jeeps and dirty,oily clothes/people are standard equipment. If all the hide is still on all your knuckles than you own the wrong rig. Clothes with weld burns is also the sign of a Jeeper.