Since there is the possibility that new users who see many imported questions and answers might think that topanswers is just a copy of SE, I think it would be a good idea to also show *who* imported a question. That way visitors wouldn't only see that a question was imported, but also that it was imported by the one who asked it or answered it (of course provided that the one who imported the question is one of the users involved in asking or answering it).
I think this would help topanswer to give a much better first impression to potential new users in that it is a viable source of new and good information, not only yet another web-archive.
You can now see who imported a post on the history page.
In other words, we've done about 10% of what I think you are asking here — but I think it is the only part we will implement. The issues of what new users think will fade over time, and now that we have [the original dates](/meta?q=457) for imported posts, I think it is clearer what is new and what is not.