The need for new style vs old style side plates came about when Tiburon began to manufacture their "topless" style frames. These frames have a recess and a raised lip on sides of the frame. See pic on the left.
Original Accurate frames as well as the original Tiburon frames with a cross bar have flat sides. See pic on right.
If you're still not sure which style plates to order, just send us some pics of your frame here, and we'll be happy to help you out.