Right you are.
I realized only upon reading the story text that it was only an endorsement by the board and that only shareholders voting will determine acceptance of the offer.
It's so sad, though, that the headline (a declarative statement) was misleading.
What else do you expect from the presstitutes? Seriesly, that form is standard operating procedure on reporting mergers, and it is technically correct. The people responsible for running Unocal (and thus, the company) did agree to the Conoco deal, and that action now "locks" the shares controlled by the company itself into voting for the deal. Generally-speaking, the next (and in this case, last because the regulatory hurdles have been cleared) step is little more than a rubber-stamp when the board says to vote for it, which makes the headline not much of a stretch.
Of course, that assumes that CNOOC doesn't try a shareholder revolt and thus a hostile takeover, but with Unocal re-opening the bidding and getting Conoco to up their bid, that would be less likely to succeed.