I can see no reason why it would not benefit from this card. As it is also able to "Crossfire" with other Machine Gun Units.
The Text of the Machine Gun Barrage card states:
All ordered units with machine guns may combat twice (ranged and/or close) and will roll 1 additional die this turn.
Units ordered to combat twice may not move or take ground this turn.
Taken from The Great War - Commands & Colors Series website.
www.commandsandcolors.net/thegreatwar/
Page title: Machine Gun Barrage - The Great War - Commands & Colors Series
Page link:
www.commandsandcolors.net/thegreatwar/th...ine-gun-barrage.html