From the Life Magazine collection hosted by Google.

Unfortunately, the image was made (reportedly) in 1956, just a year or two before the Gap-Filler Annex would be constructed. Its operational date is given as 1958.

The GFA site would be in the photo`s lower center, in that light area.

If nothing else, this aerial photo shows what the area looked like in the late 1950s when the radar facility was constructed.