Overclock Radeon 6770m (mobile)?

I am well aware of the implications this may create; heat and high power consumption. I have been around laptop/desktop hardware for quite a while. My question is, is it possible to overclock the 6770m (mobile); in other words does ATI unlock the clock speeds on its mobile chips to be overclocked? I am planning to get a laptop pretty soon with this card and wanted to know if I could bump up the clock speed by 25, 35mhz to sqeeze out just a few more frames. I am well aware many people think this is a bad idea.