The standard answer for whether asking duplicate questions on SO is valid is no (obviously) but that is because SO strives to be objective and a good answer to a technical question should always remain a good answer.
But on meta the aim is to ask questions about the way the site works and is used. And the policies for site change and evolve over time so that a question asked in 2011 about the same subject can have a different answer than if the same question were asked in 2010 or 2009.
For example in 2010 questions were allowed if they were subjective, but not argumentative but in 2011 moderators close or lock such questions retrospectively.
I know that some people suggest that a bounty on an old question is a good idea, but on meta I don't see how disturbing a slumbering senior question who was right in his day with new-fangled opinions helps - should all the old upvotes then be re-appraised given the Newspeak of the day?
So my question is (for the reasons stated) within limits, can duplicate questions be safely asked on meta?
As an aside, is the tag 'exact-duplicates' SO's contribution to the whole 'going-forward' debacle?