it depends what type box it has. if its a C series box (4age, including 20 valve) then it will have a shaft through the center but its almost never for LSD. heck even standard ae82 gearboxes have the shaft through the middle and none were factory LSD.
if its a E series (GZE boxes) than its most likely a LSD if it has a shaft through the center.
but the definite way to tell with any series box is put it in neutral, put a shaft in, turn in clockwise direction and if the other side spins the same way then its LSD, if not then its NON-LSD.