Is D300 really using sony sensor?

Many seem to assume that d300 is using sony new seneor. But hey, in case you have not notice, they are different (in reported data at least). d300 has 12.3 (4288 x 2848 ) effective MP, and sony sensor has 12.47 (4320 x 2888). Mistake, or the sensor really comes from somewhere else?

Where is it coming from then. Not likey Nikon itself, Fuji, Kodak, or even Canon?