Looks like it could be so, sooner than we might know. Either that or someone over at Nikon USA slipped up and put screen shots up of something they shouldn’t have.
Edit: The link has already been removed on the Nikon site. Seems fishy.
(The former link: Nikon USA Website)
It clearly says “D300S” in the upper right hand corner as well as in the lower corner above the SD logo. (It is rumored to have SD and CF card slots for dual media capacity.) Also upon comparison, the histogram screens are quite different than the current D300. It seems to have a zoom function with a pan/scan feature to inspect the image with the live histogram showing the selected regions. This should come in handy for landscape photographers where it may be difficult to judge the exposure of bright areas of a photo while working in daylight. (Now if someone could make it easy to view the screen in bright sun without adding bulk.)
Here is a link to NikonRumors.com where the rumored D300S specs are discussed. Of course they are all subject to change assuming the camera is even going to be released. NikonRumors.com D300S specs
Hmm… Now how can I get my hands on one of those? If only someone at Nikon loved me. (Edit: If someone at Nikon loved me, they’d send me a D3x and a couple new lenses to play with hint hint nudge nudge.)