You can check if its LSD by turning the wheels.
Jack up the rear of the car, so that both rear wheels are off the ground. Take the car out of gear, and put down the hand brake.
Turn one wheel, if the other wheel turns in the same direction, u have your self an LSD diff. If it turns in the reverse direction, it is an open wheeler (single spinner).
CAUTION: Slippery When BOOSTING!