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:
(http://www.saacforum.com/gallery/52-091218185557.jpeg)
aka.."The Breadwagon " ?
Advanced design? I suppose. Pretty? Not. You need to see this thing in person. I have. It's very strange and not attractive. My first reaction was...why?
Looks like a SUPER CAR station wagon... LOL
I like the "pickle fork" useage.
Still my favorite. Too bad it only exists as reproductions. Today they'd call it a shooting brake.