15 men drawn from each of 64 companies of the three regiments of Guards: 1st (Grenadier), 2nd(Coldstream) and 3rd(Scots). The titles in parentheses may be anchronistic. They were NOT one "Grenadier Guards" battalion.
They were formed into two battalions untill after the battle of Guilford Courthouse when they were consolodated into one, due to losses. Their battlefield record earns them the title Guard.
Total EM strength at start 960. This makes them two four element Bopping Battalions, and a new unit model, of Elite family.
http://www.reenact.com/bghistory.html
A website source with the details. Much other reading indicates their fine combat record.
Commander 76-77 Matthew, 1781 O'Hara.