I have been told by a mechanic that my rear is not the original that came with the car. It is a mono-learf perch with the rear control arm brackets on the underside of both sides. Only the Pass side control arm is installed. There are two eye holes on the top side of the differential. This is what makes him believe that it is not the original. He also saqys he sees weld seams at the ends of the tubes right near the backing plates. Any idea as to who is right?? Thanks