i didnt know there was a difference until i borrowed an aus spec one.
with the dimmer dial (the part around the bit you turn for the lights) the JDM ones click. but the aus spec ones dont. JDM windscreen wiper switches are different than aus spec too.
with the aus spec one i borrowed i cannot change the dimmer (even the plastic dial might be different too)
switches are different design too if you take them out to compare.