I very highly doubt that. Whatever the DLC will be, the way GStaff's post is written, it will be only for XBox, forever. And I highly doubt that a combined DLC of the pre-order fluff would be it.
Not for PC, or PS3, ever. Not very cool, this trend has been showing up a lot lately, and I think it's pretty chintzy. As a player, regardless of my platform of choice (PC for me), I want the opportunity to experience all of the official content.
Again based on what facts? I cite the most recent http://www.avaultpodcast.com/ in which Pete Hines speaks Directly to this issue. Listen in if you don't believe, but they speak Specifically about doing something with the pre-order packs. If you have better facts, please share them.
In actual fact Bethesda, again according to the same source, gets complaints about the pre-order packs and Pete even takes a beating from the reviewer over the fact that once sold-out, the pre-order content is locked forever from those that might want it. I would argue; What a Better way to give MIcrosoft an exclusive content deal that Didn't Really Matter to the game as a whole? Makes Microsoft happy as they get to sell something exclusive and feel good about themselves, while the people that really play and know the game won't give a damn about 1st level equipment after Nov 1st (or sooner).
So coming at this from the facts and Not assuming Bethesda is some evil beast, I stand by my GECKulations.