For anyone who's been burned by this issue-
I took some time out this morning to write a pretty in depth letter to Best Buy corporate, including the CEO himself to address this problem. I even sent pictures of the listing, my receipt, the order sheet the store taped to the game (all which read Fable II Platinum Hits) and a photo of the standard edition I was handed at the store when I picked the game up. I also sent a photo of the actual Platinum Hits version so they see the difference. I made it a point to let corporate know just how bad something like this makes them look.
I got a call from the general manager at my local store within 2 hours of sending the email. He honestly had no clue what the difference was between the two versions, but once I pointed it out to him with the photos I emailed, he apologized for the issue and told me he was going to have corporate send copies of the Platinum Hits version to the store so he can correct the issue.
I hear that some stores did actually have the Platinum Hits version, so the deal is legit, the problem is 1) The system isn't differentiating between the two versions when you select store pickup (because they're using the standard sku), and 2) Apparently, few people at Best Buy actually understand that the Platinum Hits version actually has extra content that the Standard version doesn't.
It's ridiculous. It looks terrible on their part, but at least from what I've found it isn't anything malicious, and they appear to be ready to correct the problem.
I won't post the corporate email addresses I used here b/c I don't want to flood their mailboxes and they appear to get the point. If you bought into the deal and still have the standard version they gave you, AND the receipt, I'd advise returning to the store with a photo of the Platinum Hits version highlighting the extra content, and they should make this right.
Good luck!