No, he wont be able to unlock more cores. You are confused. His CPU only has 2 cores, you cant create more. You can Over-Clock a CPU but you cant add more physical cores to it. There is a technology called hyperthreading, which take the number of threads a processor has(how many tasks it can do at once time, and doubles it.) Which is why you see the I-3,5,7 cores saying dual core, but 4 threads.. or quad core and 8 threads.
but to the original question... there is a fairly negligible performance differrence batween ddr3 1033 and ddr3 1800oc, maybe about 15%. very few applications can properly utilize ram frequencies past 800mhz.
anyway, there are no current amd processors which *officially* support ddr3 1800mhz speed ram, though some x3 or x4's *may* be able to utilize this speed if overclocked. i say *may* because every individual chip overclocks differrently. overclocking is NEVER a guarantee. a 1333mhz compatible x3 or x4, if overclocked around 28% would overclock the 1333mhz ram to 1800mhz, but a 28% overclock is very rare. more realistic overclocking expectations are around 10-15%, though overclocks even as high as 50% are occasionally seen. still, the differrence between 1033mhz and 1800 mhz ram is pretty negligible, and overclocking often requires a better heatsink, more fans, a better vantilated case, lots of patience and/or a bit of tolerance for the possibility of burning out your hardware.
dual core Athlon/Phenom II's are only guaranteed to be compatible with DDR3 1033mhz max, while triple and quad core (x3 and x4) athlon/phenom II's officially max out at ddr3 1333mhz. since the regor cores are definitely NOT x4's with 2 disabled cores, but dual cores from the start, i think its a pretty safe bet that the listing of the 1033mhz ram is pretty accurate.