I have excerpt from a book called Lumpkin Lore, which indicate that these Roberts are the same..
.Page 20 Entry 11112 indicates Robert Lumpkin b. 11/25/1756, King & Queen Co. Va, m/1 Halifax Co, Va. ca 1773 Drusellar Hendrick, daughter of John Hendrick.
The Bible record of Anderson Lumpkin
Entry 2 indicates Robert Lumpkin b. 11/25/1856 ( it must have been a typographical error since he was born in 1756), Kind and Queen Co. Virginia, d.11/12/1842, Randolph County, Ind. dau. or Richard and Elizabeth ( Oliver) Forrest. Robert and Elizabeth are both buried in the old Losantville Cemetary, Sec. 18, TWP.18 Range 12, Randolph Co. Ind. Tomb Stones were in good condition in 1968.
Except for the typo evident because these dates seem to match....?