drac2k:
Your WWII estimate is correct. The 259th Medium Maintenance Ordnance Company saw action in Morotai and the Philippines during WW II. The original posting box is a real bonus.
Ian.
Reference:
Lida Mayo.
The United States Army in World War II. The Technical Services. The Ordnance Department on Beachhead and Battlefront. Center of Military, U.S. Army, Washington DC (2009) Accessible online
here.