Okay - here's some information...

Name: Richard Robertson
Father: William Robertson
Mother: Rebecca Sutfin
Birth Date: 15 Mar 1850
City: Nashville
County: Brown
State: IN
Country: USA

Name: Richard Robertson
Spouse: Kathrin Ester Lutes
Parents: William Robertson , Rebecca Sutfin
Birth Place: Brown CO, Nashville, IN
Birth Date: 15 Mar 1850
Marriage Place: Nashville, Brown CO, IN
Marriage Date: 15 Mar 1876
Death Place: Bedford, Lawrence CO, IN
Death Date: 20 Mar 1928

1850 United States Federal Census
about Rebecca Sutfin
Name: Rebecca Sutfin
Age: 14
Estimated birth year: abt 1836
Birth Place: Indiana
Gender: Female
Home in 1850(City,County,State): Perry, Monroe, Indiana

Rebecca Sutfin
Born: 1821
Weddlesville, [county], Indiana, USA
Died: 6 Jun 1893
[city], [county], Indiana, USA
Spouse
William Robertson
Born: 7 Sep 1819 in Clybrn, [county], Tennessee, USA
Died: 3 Sep 1886 in Jackson, [county], Indiana, USA
Marriage: 6 Jun 1844 View Info
Children Sex Birth
Richard Robertson M 15 Jul 1850 in Nashville, Jackson, Indiana, USA
Perry Robertson M 5 May 1863 in Elkinsville, Brown, Indiana, USA

Like you, I am not finding anything that pin-points which of the William Robertson's listed might be him, without actually going through all of the files.

JR