I did serve at the battalion level with a combat unit. 1st Recon Battalion 1st MarDiv. It was before Nam however.
I worked in Message Center/Crypto which brought me in contact with the CO and all staff officers. S-2 as well as S-1, S-3 and S-4.
Since we were HQ we normally had a perimeter around our position during field exercises. Now that would mean that Murtha's position (if he was at HQ at the time of his injuries) was overrun or shelled from a distance. That's why it would help to know the outfit he was in and where in Nam he was deployed. We could then go to his outfit's Web Site and get their history.
Or better yet contact some Marine Nam vets who served in his outfit at the same time.
If Murtha won't say what outfit he served in then he's another Kerry.
I did a quick Google search and this was all I could find out
US Marine and decorated Vietnam War veteran
Murtha remained in the Marine Corps Reserves. In 1959, then-Captain Murtha took command of the 34th Special Infantry Company, Marine Corps Reserves, in Johnstown. He remained in the Reserves after his discharge from active duty until he volunteered for service in Vietnam in 1966-67, serving as a battalion staff officer (S-2 Intelligence Section), receiving the Bronze Star with Combat "V" for valor in combat, two Purple Hearts and the Vietnamese Cross of Gallantry. He retired from the Reserves as a colonel in 1990, receiving the Navy Distinguished Service Medal.