From ""THE ARMY AIR FORCES In World War I1 Volume One PLANS AND EARLY OPERATIONS JANUARY 1939 TO AUGUST 1942", PREPARED UNDER THE EDITORSHIP OF WESLEY FRANK CRAVEN Princeton University JAMES LEA GATE University of Chicago, 1947, page 632.
It already had been agreed that construction costs in the development of bases for American occupancy would not be charged to the United States. Ownership of all installations in the United Kingdom would remain with the British, AAF units being considered as tenants, and the financial considerations involved were handled under the reciprocal aid provisions of the lend-lease agreement*.
Under the arrangement, the Americans accepted RAF standards of accommodation, though as time passed, modification in individual instances would be made. During April, an air section of the office of the chief engineer, USAFBI, had been set up with responsibility for dealing with the Air Ministry in all matters pertaining to construction for the Eighth Air Force. The new section established liaison with the Air Ministry and with the Ministry of Aircraft Production, which had been made responsible for the Construction of base air depots. When the European Theater of Operations under Maj, Gen. Dwight D. Eisenhower succeeded USAFBI in June, responsibility for problems of construction for American units passed to the chief engineer, ETO, where it remained throughout the war.
* Air Ministry, Joint Organization and Maintenance (United States) (S.D. 348), June 1942 (JOMUS), Sec. XLIII
Would the Air Ministry have have given the RAF notional ownership and thus the RAF prefix mentioned in the document? It's established the USAAF didn't use the RAF prefix themselves but perhaps RAF documents may have had they been the ones given custodianship by the Air Ministry.
Interesting piece of history
XV490, though no definitive answer, unless someone can find a copy of the Air Ministry document I reference above.