Not sure how may GT's there are, but suffice to say: very, VERY few. Less than a couple-dozen, to be sure. There was an unofficial registry of Aussie Falcon owners in the US online a while back, but
AFAIK that page is down.
We figure there are just over a 100 or so Falcons (XA/XB/XC Coupes/Sedans/Utes) in the US and Canada at this point...