
It's a photo of a scale model.
Model 18 was General Dynamics' compliant submission to the VFAX requirement, it was basically a 108.8% scaled up and navalised F-16 with Krueger leading edge flaps, blown flaperons, bladder tanks, F401 engine, long range radar and Sparrow capability. I have a photo of this model with dual Sidewinders on the wingtips and underwing Paveways.
V-1600 was later, and done in partnership with Vought (LTV).