Service School Question

Post
ecaps
Cadet
All,
During WWII if enlisted in the Army Air Corps, would you have been assigned to a Service School?
 
Reasoning behind this my grandfather enlisted in Dec 1942 with AAC at Ft. Francis Warren.  I have a picture of him in his dress uniform with AAC collar discs and unknown DUI pin.  However, his discharge papers list NONE in the 41. Service Schools Attended box. 
 
I know sometime during his service, he ended up in the 18th Infantry Regiment. His only campaign credit is Central Europe which was the end of the war, but he was in Europe from Sept '43 to Dec 45.  I'm wondering if there is a possiblity he was still attached to some unit of the AAC during that time. He spent approximately 9 months in the USA before going overseas. (At least according to the information obtained from his discharge papers.)
 
Any help/insight would be appreciated.