Good Question.
In short, the self-installer client is an ActiveX control, so it doesn't actually install any plugins to Outlook itself. The result of this is that Offline Vaults and PST user initiated import (push) don't work to the best of my knowledge (in my experience I haven't found a great number of clients using this since ActiveX is normally blocked anyway).
So this leads on to a 'no' for the next question as well I'm afraid :(
IMHO, push out the latest client via GPO, SMS or altris etc. You can do this ahead of enabling mailboxes for archiving as the user extension remains dormant until that time.