There are three Samuel Hickmans in that time span and in that area. Samuel Hickman b. est 1740 m. Margaret Milliken in abt 1763. She was baptised in 1743 in St. David's Parrish,Horry Co, SC the daughter of Moses Milliken. Source:Family Bible of Moses Milliken which is in Library of Congress. After the War Samuel returned to South-Eastern NC, possibly Brunswick.
The second Samuel Hickman is b. 1775 and could be Samuel and Margaret's son.
The third Samuel Hickman was born in 1848 s/o Anna Hickman who is found later living in the household of Samuel Hickman b. 1775 in Brunswick Co.
Confusing isn't. Maybe Carolyn can explain it better than I.