It is most likely LSD, however, single spinners can do this sometimes as well, and LSD diff can sometimes leave only one mark if the clutches slip.
To be 100% sure, jack up both rear wheels at the same time with the car in neutral, and park brake off. Turn one wheel. If the other turns in the same direction, it's LSD, if it spins in the opposite direction, it's a single spinner.
CAUTION: Slippery When BOOSTING!