The article says it was used. The M-72 is a single use launcher. Once it is fired once, the launcher is trash.
It probably is the one Dirty Harry used to blow up the guard tower at Alcatraz Island.
Yes, the LAW is considered and issued as a round of ammunition. Once fired it is useless and may be discarded.
Incidentally, the LAW has regained popularity during the Iraq war. It is still cheaper and lighter than newer weapons and works well against what the enemy is equipped with.
http://www.defenseindustrydaily.com/2005/03/marines-fought-the-law-and-the-law-won/index.php