It would seem to be a good assumption that his name was legitimately out there, considering reports that a handful of teams thought they were going to get Oswalt. Credible? Maybe not. But I'm not sure a couple of newspaper reports (even if one is the NY Post) are less credible than Drayton McClane speaking on a radio station after the trade deadline when the motive for damage control is very high.
I'm going off their history. They've never gotten rid of a player of Oswalt's caliber when they were this close. Nor do they have a history of making terrible trades like Oswalt/Everett/Ensberg for Tejada. There were also MLB sources who said that Oswalt was not brought up by the Astros in the Orioles talks. I think it has to do with Purpura going the route of the Braves G.M. who says he never flat-out says no to a trade. That's what happened here and the media turned it in to we were shopping Oswalt. Fans and Roy O. faint.