tedster - 10:07 pm on Sep 13, 2012 (gmt 0)

If the content is no longer actively served, and then it re-appears on a different domain, it's not duplicate. I'm sure Google has extensive historical data - but we don't know how much or how they use that data. All iinds of things are "possible".

I can tell you from experience that if old content that is gone is now put up at a new URL, that also does not cause ranking issue.