The # of GTs built was significantly increased in the 2006 MY.
2006 Model Year Production 165,762
87,314 V6,
78,448 GT
2007 MY production started 2nd week of June 06, so the 07 has been in production for 7 months. Planned production rate & GT mix is about the same as for MY 06 with the addition of the GT-500. So figure that around another 46,000 07 GTs have already been built as well as 51,000 V6s.
So to answer your original question, as of last Friday, approximately 185,000, S197, Mustang GT's with 3V 4.6s have been built.