L Garey
I can see the strip you refer to. Yes, it could have been the one I heard about. However I did drive to Umm Az Zammul a couple of times (2-day trip each way then) on business, so to speak, and did not see it. But then, unless you happened to choose that particular salt-flat as a route, you would miss it.
I have no recollection of any exploration in that area in the late 60s or 1970s, but that's not to say there wasn't any, especially before that time. In my time the activity was all in or South of the Liwa, and in a variety of places to the North and West of the Liwa up to the Saudi and Qatari borders on land, and the coastline to the North.
But if there was, there are still lots of ex-GF pilots around - probably retired - who would have flown there in F27, DC3, DH Heron, DH Dove, B80, F27, BN2A or Skyvans on charters for ADPC or an ADPC contractor such as Schlumberger.
Alternatively the strip may have been created in the 1970's or later - fairly secretly until Google Earth - by and for the ADDF as an advance base, which seems more likely to me. It might also have been intended for Shaikhly hunting trips, but that area is not famous for bustard as far as I know; the hunting usually took place much further South, in the Sultanate.