For what it's worth.....

The unit Bush was in was known as a 'Tiffany' unit and about the only way anyone could get into it was to be the son of a well connected Texas.

The joke was that the unit was being held in reserve in case the Veitnamese ever attacked Houston.

If you were not well connected you could still get in, but there was a three year waiting list.

I knew several people that tried to join at the same time Bush was a member of this unit and this is what they told me.