I was close:
The 28th Infantry Division Band distinguished itself during WWII. During the Battle of the Bulge, the divisional command post at Wiltz, Luxembourg, came under severe attack. Members of the 28th Infantry Division Band took up arms and fought as part of holding line around Wiltz to stop the German advance. The band put away their instruments, dug foxholes and picked up carbines. A clarinetist, Private First Class Collins, manned a bazooka and then drove a truck loaded with the band’s music. He was going to save the music, but 10 miles out of Bastogne the convoy was ambushed and all the music burned. Only 16 of the band’s 60 men survived the fighting in the Ardennes.
The 28th Infantry Division Band was not the only band involved in the Battle of the Bulge. The 101st Airborne helped hold on to Bastogne preventing it from falling to the Germans. The 82nd Airborne Division Band was caught in the battle after being sent to the Ardennes for R & R. The 82nd front line was stretched thin. The 82nd Airborne Band joined the depleted front line to hold off the German spearhead. The band helped hold off two German Infantry Divisions and a Panzer Division.
Yes, it was the 28th Inf Div band...and not a Marine among them. ;) There is a nice museum in the castle at Wiltz where the Div HQ folks fought a desperate and successful delaying action.