It seems likely that this 1880 census is Samuel and his family: "United States Census, 1880," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/M6XL-8PB : accessed 19 February 2015), Samuel Rodgers, Round Grove, Macon, Missouri, United States; citing enumeration district 120, sheet 319A, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d.), roll 0701; FHL microfilm 1,254,701.
The differences: The son born in 1864 is now named Samuel, not Clendenen. Fred born in 1866 is missing. Mattie born in 1868 has become Martha. The last name has become Rodgers.
In the census index for 1860 Samuel is 27, in 1870 he is 28, I need to see the actual 1860 scan.
Also, based on the marriage record of Clendenen and Clara, it's possible that Harriet's maiden name is Rodgers.
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