Look at the trigger slots, there is a left and right slot. In a perfect world you could change the triggers from slot to slot and have it either way, however most triggers are bent inwards ever so slightly so that they line up below the slots. I learned this when I tried to reverse the triggers on a gun and had the reversed triggers noticeably sticking out from the sides of the trigger guard.
Steve

Approach life like you do a yellow light - RUN IT! (Gail T.)