who are martha Johnson's parents ( actual surname is Johnston not Johnson so see other comments)

Question

1870 US Census, TN. Thomas Johnson 79y b NC, Martha Johnson 81y b SC. Census taken in TN.
It appears all other details(yr,location,age,birthplace) are correct excepting the surname should read Johnston and not Johnson)
Name:     Thos Johnson
Residence:     , Coffee, TN
Ward:     5th Civil District
Age:     70 years
Estimated Birth Year:     1790
Birthplace:     NC
Citing this Record

Comments

Any chance this is the correct person?

Thomas Johnston mentioned in the record of Thomas Johnston and Martha Terry

Name	Thomas Johnston
Spouse's Name	Martha Terry
Event Date	06 Nov 1827
Event Place	Caswell, North Carolina

Citing this Record

"North Carolina, Marriages, 1759-1979," , FamilySearch (https://familysearch.org/ark:/61903/1:1:F8P8-NPD : accessed 10 August 2015), Thomas Johnston and Martha Terry, 06 Nov 1827; citing Caswell, North Carolina, reference item 1; FHL microfilm 478,486.