David Montgomery Davis

i need some help with this man please.
b. 1813, Ga. married Sarah A. ? b. 1817 Ga.
buried, Old Flatwood, Walker Co. Al.

in the 1860 census had children
George Jackson, b. 1838
James J,. b. 1842
David T. , b. 1844
John Melton, b. 1846
May E., b. 1848
Levi R., b. 1852
William T., b. 1857
Aaron B. , b. 1858

does anyone know for sure if David M.'s father was George Cook Davis, b. 1789, d. 1876, Morgan Co. Ga. ???

and how if any does David M. relate to Harmon Davis who married Nancy Posey ??

my family has always said that the Davis buried at Old Flatwood were related and Sara V. Davis, dau. of Harmon was the grandmother of James R. Lincoln Martin....my paternal grandmother's first husband.