October 1942 is the date on the National Archives and Records Administration’s (NARA) microfilm of the outboard profile drawing (above) from the Federal Shipbuilding & Dry Dock Co. set for 1630-ton DDs 483–490 (Aaron Ward, Buchanan, Duncan, Lansdowne, Lardner, McCalla, Mervine and Quick), commissioned the previous May–July. The drawing, which contains Aaron Ward’s hull number, shows four 5-inch guns and one quintuple torpedo mount.
   The corresponding general arrangement drawings (below) also show side-by-side 40mm twin Bofors anti-aircraft guns aft, but this armament was not yet available before June 1942. Thus at least Aaron Ward and her five DesRon 12 sisters (DDs 483–488) initially carried the earlier fit of a 1.1-inch cannon to starboard and a 20mm single Oerlikon to port in this position.