I have no solid information on this question myself, but Eric Milgram over at Pharmaconduct is trying a wisdom-of-crowds approach. He's got a survey up of which sites people think will close, and it'll be interesting to see how well this matches up with the eventual reality.
At the bottom of the list, naturally, is Pfizer's (NYSE:PFE) site at Groton. I think we can safely predict that this one will stay open, but the New London site, right across the river, doesn't fare so well in the voting. In fact, it's the second-highest-ranking Pfizer site on the list, outdone only by St. Louis (the former Monsanto). The rest of the top contenders are all Wyeth, led by Madison and Princeton.
The "wisdom of crowds" method doesn't produce wisdom out of thin air, of course - it's supposed to be a more efficient way of getting to information that's already out there. In this case, though, I don't think that the information is out there, so this should be taken as more of a poll of sentiment, which is certainly how it's presented. To that aspect of it, one thing that Milgram's already noticed is that people who are currently employed at either Pfizer or Wyeth tend to believe that it's those other guys who are most likely to have to close some facilities. We shall see..