why are there locked cores in the first place?
They were locked because the cores were not fully functional, were faulty in some way, or they were disabled simply because more people wanted to buy dual-cores and if AMD can sell more chips at a lower price, it's better than selling little or no chips at a higher price. If you got a chip because of the last reason, then it's basically a 955 for 2/3 of the price.
I can't wait to start seeing Phenom II x2 555's overclocking in this forum. I've seen pre-release ones go to 4.2ghz without touching 1.45V.