A hardfork occurs when the new coin specs go into effect...not when you release a new client version with it set to change after a certain point.
So the question is...when does the hardfork actually occur....could look at the source but just wanted to point out the hardfork did not actually take effect yet.
Edit: To answer my own question...hardfork will actually take effect at block 575000. Update before then or you will be on the wrong chain.
Hard fork occurs when new clients are released that ignore the clients with the old protocol. That has already occurred. The chains are already diverging. If you make a transaction on the 1.2 chain right now, it will not be in the 1.3 chain. If you mine on the 1.2 chain, those will not be on the 1.3 chain. 1.3 clients currently ignore 1.2 clients.