Here is some information on Harris and Cynthia Allcock documented by my grandmother.
Harris Allcock - He was born July 24, 1852 and died on Feb 8, 1908.
Cynthia Jane (Edwards) Allcock - She was born Oct 25, 1857 and died on July 22, 1913.
Your grandfather Richard Nelson Allcock must have been the brother of my great-grandmother, Annie Mae (Allcock) Lamb.Annie was born on March 2, 1890 and died Jan. 24, 1969.Annie married Joe Lamb (b. Aug. 7, 1886 - d. Oct. 23, 1967).Joe and Annie lived in Graves County (KY) and later McCracken County (KY) until their deaths.They had five daughters (Ira, Cleo, Marie, Omega, and Mary) and two sons (Cratis and James).Marie (Lamb) Kirksey was my grandmother.
I cannot verify the following but I found an entry which stated that Harris' parents were J.N. Allcock (b. 1826 in KY) and Elizabeth J. (Munk) Allcock (b. 1830 in KY).This entry also stated that Harris and Cynthia had a son named Bert A. Allcock who was born in 1893 (Graves County) and died in 1932 (McCracken County).
If you are interested, I have a copy of a photo showing Harris and Cynthia.