I had a lot of people in my area join the Reserves to avoid the draft. They opening bragged about it to the ones that were on active duty. BUTTT their unit got activated and they beat most of the people who had enlisted to Vietnam.
I think there were some Air Guard units that were activated. Most of these guys flew F100's. There was some in Korea in 68/69 because we got to watch one crash but the pilot did get out. He was not real happy.
Indiana Air National Guard flew regular runs to Nam and some elements were activated. Otherwise, the Air National Guard and the Army National Guard sat out the war (unless they missed too many meetings, yada, yada, yada)
It's the "missing meeting" part that was far more applicable to the Army National Guard that Kerry is trying to hang on President Bush.
Most Navy guys don't know the difference. Then again, most Navy guys were in the Navy because they were trying to beat the draft. Kerry certainly remembers his ambitions at the time.