I have seen this photo before (but never in this quality) and had never heard this car referred to as the "
GT-P" either.
It shows J-1 in its first "picklefork" nose design at Ford's Advanced Concepts Department.
I recently scored a copy of
MOTORCADE magazine (March-April 1966) and this was on page 11 and also on the back cover.
There was some pretty radical, futuristic thinking going on at Ford in the mid 1960's: