@mysteryman,
If Foofie had actually served in the armed forces, he would have known that. My brother, who was a fire control technician, referred to it as an MOS, but then he might have done that because i and our other brother were members of the army.
The point, however, is that Foofie was probably lying. We will never know now, though, since you have let the cat out of the bag.
The army MOS for field medic was 90A10, 91- would imply either a higher rank or a higher degree of training. Although i was trained for 90A10, i was sent to the Medical Field Service School and there trained for other MOS's, so i didn't follow that track long enough to know for certain about that.