Just out of curiosity ... do/has the Air Corps ever used the military rather than the civilian designations for aircraft that have dual designation.
AFAIK, the following current AC have dual designation;
Cessna 172 -- T41
Gulfstream IV -- C20
Beech 200 -- C12
The PC9 is designated T6 but it seems there are differences between the vanillia Pilatus build and the Raytheon T6 version.
...145