I'd like to know the answer to this as well.
No. None of the panels have a 'selected' attribute, and in general you are unable to determine it otherwise.
(The few exceptions I can think of are the Layer panel ("activeLayer") and Preflight ("activeProcess"), and Character, Paragraph, and Object styles -- these only when there is nothing selected. (And when you *have* something selected, their selection always equals that property of the currently selected object.))
There is a PagesPanel object, but there's no selectedPages property...
Dirk might have a plugin which can tell you what's selected, but I don't remember for sure...
Dirk does have such a plug-in.
I just do not advertise it because the functionality is incomplete - you can only read the selected entities of the various panels, but can't select e.g. another page/swatch/etc. Besides my activation mechanism is a pain, asking for a rewrite whenever I find the time.
Even worse, I just realised my webserver is down so I can't point you to a demo download.