The official HTC Sensation page claims that the device is features the famous HTC unibody design, but as it turns out, it might be just a cheap marketing trick. Of course there's an outside shot that SlashGear have just gotten a review unit with unfinished design, but we wouldn't count on that.
To be extra sure, we wrote an email to HTC asking for an official statement about the discrepancy between the official photos and the actual unboxings of the Sensation, but as of this moment we don't have an answer. Of course we'll let you know once we hear back from HTC.
source: GSM Arena