1989 XJ6 How do I know if

How do I know if my wife's 1989 XJ6 has been refitted with the non self leveling brakes in the rear. What am I looking for when under the car? I thought that it was changed over from looking under the hood and seeing the line disconnected. I changed the accumulator and now the back suspension is all over the road. Any connection? What is the difference (visually) of the two suspension systems?