Ed,
I don't know when or if they stopped the GT option in 1969 on the Mustang, but over the last 10 years I put together
some records of 69 GT Mustangs. The below Vin #'s and dates of production are the latest I have from each of the
factories:
9F03M217545 built July 16,1969
9T02S209307 built June 10, 1969
9R02S156764 built March 21, 1969