Hopefully without stirring too much personal emotion and certainly at risk of furthering political debate on a self-professed non-political forum:
HB99 - the Guard is commemorating a long history of our states having the ability to defend themselves. Since the colonial militia had much the same mission as the National Guard does today, the Guard claims its roots with the militia. You are correct that the modern National Guard is much younger - only 103 years old. However, our country (or state or nation or colonies) has a longstanding tradition of unity and defense of our way of life, and that's the point of the 370 year celebration. It's not a government conspiracy or perversion of fact. In fact, the National Guard website describes the whole history.