I thought the 21v was it's own unique beast. lsv hull was similar but the 21v had a different chine just above the bottom of the hull. from the rear they were shaped similarly but some subtle differences made it a different wake.
back in the day most of the feedback was that it wakeboarded better than any other hull in skiers lineup but it pretty much sucked at surfing.
gsa could be a way to improve that tho.