They seem to be correctly interpreted.
I'm asking because of some minor reasons and a major one: NotebookWrite a Cell with WholeCellGroupOpener option
I don't know any official confirmation so let me just ask if anyone knows where using string names for built in options names may fail.
Let's assume the context is only about Cell options.
As we can see, works well:
CellPrint[
Cell[TextData["Test"], "Input", "Background" -> LightBlue,
"CellFrame" -> True, "FontColor" -> Red]]
Cell expression (Ctrl+Shift+E) shows that "Background" was converted to Background but even if I manually edit the cell back to "Background" it understands it.