The main difference on the deck is the riveted screen, in these two pics, the fwd sections of the hull look very similar, but as I understand it, on the old one, the inner most spray rails stop about 3 feet short of the transom, where as on the later, they run right back to the transom, and form a kind of pad, this is the same design as the 20' Excel OCR boat.
we could get the Capitaan and Bert to take pics of the lower transom area, and post them as comparison, as it's hard to explain.