Alright, the death date for William Lusk October 7, 1780 comes from my Ancestry tree. Our DAR files are based on this really old piece of paper that states:
The Standard American Enycylopedia Vol. 7.
"King's Mountain, an eminence in York Co. South Carolina, 80 miles NW of Columbia, where the battle took place Oct 7, 1980 between the Americans, under Levier, Shelby, Campbell, etc., and the British under Ferguson. The latter were defeated with a loss of 456 killed and wounded, among whom was the commander and 648 taken prisoners."
His wife Elizabeth Vance and he had the following children,
John, William, Mary, Joseph, Elizabeth, Sarah, and Margaret.