Actually....the 9800gtx+ did come in 65nm when it first started releasing if i recall.
I thought the only difference between the vanilla 9800gtx and the + varient was that the + varient was 55nm? Are there other differences?
*update* I called EVGA and asked them about the core clock discrepancy and I was told the 9 series card actually underclocks itself while in 2d mode. I have yet a chance to test this, but i'll take his word for it for now