http://www.engadget.com/2010/04/17/iphone-4g-is-this-it/

No.

I now believe this is a prototype of the new iPhone set to debut this summer. A few key details have surfaced, most importantly this device can be seen laying on the table next to the locked down iPad in the photos leaked just days before the iPad’s unveiling, along with what appears to be a ceramic back on the unit, which Apple has a patent from 2006 for, that doesn’t limit the radio signal as much as metal enclosures.

Those at Gizmodo who have handled it (and purportedly paid the finder for it) say the resolution is high enough that you cannot make out individual pixels, and it is recognized by iTunes and Xcode as an iPhone.

However, unlike Gizmodo who are bending over backwards to try to understand this “radical departure” from current iPhone design, I do not believe this unit represents the final design. It does not bear any markings of Apple’s design language. The seams and separate volume buttons (as opposed to the volume rocker switch on all previous and current devices that run iPhone OS) are particularly homely.

Also worth noting is that under California law, you are required to notify the police and return a found item that isn’t yours, and Apple considers this stolen. Whatever ad revenue Gizmodo is making from this story, I hope it’s worth it if/when Apple Legal calls wanting this prototype back.