The event was an employee open house at Lockheed Martin. I was invited by the p.r. folks because we're simply old friends and they knew there would be some items on public display that I would find of interest (such as the models). Photographed them all, though it would not be easy for me to lay my hands on the negatives if someone asked me to do so.
I'm not absolutely certain that I remember what the model in the top image was about, but what comes to mind is a long-range, high-speed, low-altitude weapons delivery platform (something along the lines of an attack-class aircraft) optimized, to some extent, for low observables. Artist renderings of this airplane appeared in several different publications during the 1970s. The aircraft in the other image were primarily long-range, high-speed interceptor studies. Not visible in the grouping in your photo is one design calling for a Mach 3-plus recce platform to replace the SR-71.
Sorry I can't be more definitive.
All the best, Jay