I have to be skeptical on these as well, for a number of reasons.
1. If they are real, why wouldn't Apple have forced them to be taken down? Remember last year's Panther screenshot leaks, or even just the stupid display DIAGRAMS that AppleInsider had - all forced down. Not these.
2. Where is the screenshot of the new Finder? There can't be a major OS update without SOME change to the Finder, and no, an "about box" isn't going to prove anything.
3. The "lighting" affect that highlights which areas of the control panel that you can find whatever you're typing in the search box is very inconsistent - the light is a circle on some, and very ovalish on others.
4. Would you not think there'd be a control panel area for the "Dashboard" thing? Not to mention that the Dashboard looks like crap in these screenshots.