I also saw the same and believe it is the right man.

In the 1870 CD 10 census Shelby Co.,TN:
Preston Roberts- age 32, b.TN, farmer
wife Mahala- age 36, b.MO
Children (b. TN): Eddie (age & Preston (age 1)

In the 1900 CD 10 census Shelby Co., TN:
Preston Roberts- b. Oct 1839 TN (his father & mother b. VA)
Wife Mahala- b. Aug 1834 MO
Children: Henry T., Hayse & Ellen
Married 37 yrs
Noted that had total 7 children

In the 1910 CD 11 census Shelby Co., TN
Preston Roberts- age 71, widowed, servant in household of Jack Parker (b. 1836 GA, black, wife Malindy)
......I found it interesting that a 71 yr old black man was the servant of a 74 yr old black man

1910 Memphis City Directory
Preston Roberts residence was 364 Leath

I have searched several websites of death records for the state of TN and can't find him or his wife listed. Maybe they died out-of-state?