Note: This is only relevant to the default shipped VF_UM040O and VF_UM044O instance list browsers.
Method #AvListManager.AddToList has a parameter RowStyle that will add a #PRIM_VS.Style reference to the instance list row.
Additionally every #VF_LM003O instance list item has methods avRemoveAllStyles, avRemoveRowStyle and avAddRowStyle.
Refer to shipped example Example Applications -> Advanced -> Control Instance List.
The source code of the filters DF_T3005O (Column Style) and DF_T3006O (Row Style) demonstrate various techniques for styling the rows and columns on an instance list: