If you believe Tim Dierkes at MLBTradeRumors.com they are. I'm not sure what it would take to get Hunter Pence from the Astros, especially within the division. You would assume the Astros would want a decent haul for Pence, who is under team-control until 2013.
In the comments section of the post, one fan is suggesting the Buccos would have to part with Jameson Taillon or Pedro Alvarez. Others have already suggesting shipping a package including Jose Tabata. I really like Pence, but I'm not willing to sell the farm, especially not to a division rival.
And, yes, I know there have already been plenty of trade proposals throughout the site for Pence in numerous other threads. But this time there's proof, apparently, that the Buccos have been keeping tabs on him.