The comments from the following answer gave me a clue:
What is the difference between the data and dataSource in knockout-kendo grid widget?
It seems like you can use data and dataSource in tandem if you want to specify this behavior:
kendoGrid: {dataSource:{sort:{field:'Col1',dir:'asc'}}, data: grid.Rows, sortable: {allowUnsort: false,mode:'single'}, columns: grid.Columns}