Its not fake, Best Buy Mobile posters often look like that. While I'm not a store employee, I do a lot of work merchandising and doing marketing projects in Best Buy, and promotional material is not always professional looking or accurate, a lot of it looks thrown together and often has errors. That's just the way it is. In fact, there's a Best Buy I work in where there's a poster of a bunch of phones above the Thunderbolt on display, and there's a picture of an HTC phone (can't remember if its the Inc, Evo, or T-Bolt) and its running iOS. Then again, the computer kiosks use large tv's stood on their side with a fake bezel that run an iOS looking skin over Windows, so maybe its just an Apple-obsession.
But still, promotional material, especially for phones, is not always accurate or professional looking. While a little ridiculous, this kind of thing is not uncommon. I see no reason to think that poster is fake, and it brings us no new information. It'll come out when it comes out, and unlimited data will not be an option unless you already have a Verizon smartphone. It will probably have a pentile screen, and it will be huge. I'll stop there, as I'm sure most of you already know that I've lost interest in this phone long ago, though I am glad to see they're finally bringing it out to those who stuck out the wait, or just found out about it.