There's a bit more to it that I didn't consider... (my bad!)
AutoFilter
Must be used with a range of contiguous cells
This toggles the filter dropdowns
FilterMode
True if rows are filtered;
False if rows are not filtered (even when the dropdowns exist)
AutoFilterMode
True if dropdowns exist;
False if no dropdowns exist
So.., my reply should have been as follows...
With ActiveSheet
If .AutoFilterMode Then .UsedRange.AutoFilter '//turn it off
End With 'ActiveSheet
If rows are filtered:
ActiveSheet.FilterMode is True
ActiveSheet.AutoFilterMode is True
If rows are not filtered:
Dropdowns exist:
ActiveSheet.FilterMode is False
ActiveSheet.AutoFilterMode is True
Dropdowns do not exist:
ActiveSheet.FilterMode is False
ActiveSheet.AutoFilterMode is False