Rolex is very close but just a bit dated, the Army has gotten rid of the specialist rank with the exception of Spec-4, which is now only referred to as Specialist. Otherwise he was right on, the specialist were ranks designed to recognize technitians and admin folks, and the rank went all the way to Spec-8. The Army eventually realized this duel rank system was bad business and began phasing it out.
Gary Owen was, like mentioned, an Irish drinking song that was adopted for the 7th US Cavalry, it is still considered the official music of the 7th US Armored Cavalry.