Hello everyone.
Since I had never seen the term "Adjutant" used to designate the G-1/S-1 in any of the primary source documents I've read over the years I decided to look a little further into the matter.
Here is a little more information about the use of the term "Personnel" to refer to the G-1/S-1 staff position.
338.3.1 Records of European Theater of Operations U.S. Army
(ETOUSA)/U.S. Forces European Theater (USFET)
Textual Records (reallocated to RG 498): Decimal correspondence, interrogation reports, personnel rosters, awards files, and other records, 1941-47, of the General Staff Secretary; the following general staff sections: G-1 (Personnel), G-2 (Intelligence), G-3 (Operations), and G-4 (Logistics); the following special staff sections for administrative matters: Adjutant General (including the Postal Division), Civil Affairs, Finance, Historical, Judge Advocate General, Provost Marshal, and Public Relations; the following special staff sections for technical matters: Engineer, Ordnance, Quartermaster, Signal, Surgeon General (Medical), and Transportation; the General Board; the General Purchasing Agency; Theater Service Forces European Theater; and Communications Zone ETOUSA. Escape and evasion reports of the MIS-X (Military Intelligence Service, Escape and Evasion Section) Detachment, 1943-45.
[url="http://www.archives.gov/research/guide-fed-records/groups/338.html#338.3.1"[/url]
A check of the glossaries contained in several US Army in WWII publications of the US Army Center of Military History ("Green Books") shows the use of the term "Personnel" for the G-1 staff position for divisional and higher headquarters.
Of course, the S-1 term is the same as the G-1, but for units small than divisions.
Hopefully this clarifies that "Personnel" was the standard term for G-1/S-1 rather than "Adjutant."