It looks as if there are surviving records of the baptisms of two children of Alexander Smith and Catherine Rose; Alexander on 4 March 1803 and Catherine on 3 August 1806.
In the 1841 census, at Achlaiscoil, Daviot are Alex Smith, 70; Isabel Smith, 25; Alex Smith, 30; James Fraser, 15; Margaret Clunas, 20 and Catherine McDonald, 10.
At the same address in 1851 are Alexander Smith; 82; Alex Smith, 46; Mary Smith, 39; Catharine Smith, 6; Alexander Smith, 4; Marjory Smith, 2; John Mackintosh, 21; Janet Cameron, 21; Sophy McKenzie, 32. All the Smiths were born in Daviot.
So it looks as if Catherine Rose must have died before 1841. The chances are that she had died long enough before her husband for the family to be unsure of her date of death when they put up the gravestone. So she is almost certainly in the same grave in Dunlichity.