I don't think so, I heard they are putting new chip on R9 280 and should reduce the power usage.. we just have to wait for now..
There is no such thing as a R9 280. Nothing is listed on manufacturer's pages or retailer websites.
The rolling update of a new chip is for the R9 280X.
The chip and naming progression are as follows:
Tahiti XT (7970) -> Tahiti XT2 (7970 GHz, early R9 280X) -> Tahiti XTL (R9 280X)