NSA probably did buy some SUN workstations. They'd buy a few of anything in those days.
I was at an aerospace company that made satellites and ground stations back then, and we had a few Sun workstations in the early 1980s. One had a TV-resolution color display in addition to the black and white display. Someone ported an orbital elements program plotting program for satellite orbits and positions, and the positions of the ground stations, providing a real-time display. An Air Force general was visiting, and demanded that the entire machine be immediately moved over to the USAF Satellite Control Facility (the old "blue cube" in Sunnyvale), which was still running on the 1960s technology used by NASA for Apollo. This was done, and the in-house machine was replaced at USAF expense.
I was at an aerospace company that made satellites and ground stations back then, and we had a few Sun workstations in the early 1980s. One had a TV-resolution color display in addition to the black and white display. Someone ported an orbital elements program plotting program for satellite orbits and positions, and the positions of the ground stations, providing a real-time display. An Air Force general was visiting, and demanded that the entire machine be immediately moved over to the USAF Satellite Control Facility (the old "blue cube" in Sunnyvale), which was still running on the 1960s technology used by NASA for Apollo. This was done, and the in-house machine was replaced at USAF expense.