unfortunately, the national guidelines were revamped/rewritten/reformatted with the 2005 rule book and the addition of masters and juniors as required classes is a misprint and should not be there. Masters truck and Juniors buggy is and has been for several years an optional class to offer at any national event.
This was the information given to the host track and documented with the Excomm. Regardless, the host track was given permission to not offer Master's as it is not a required class.