Letters of George Lockhart of Carnwath argues that DNB in error in birth date and that death occured sometime after January 1732 of wounds received in a duel.
Data provided by the ESTC/BL
His Letters of George Lockhart of Carnwath, 1698-1732, 1989 p. xiii (b. 1681, d. 1732)
DNB (Lockhart, George, 1673-1731; of Carnwath, Jacobite and author)
His Memoirs concerning the affairs of Scotland, 1799 t.p. (By Mr. Lockart)