It means you "MIGHT" have to oc the processor to get to those speeds. In intel's eyes anything over 1600 is an OC in memory, yet they intentionally put a setting called XMP that can clock the memory much higher than that without the user having to do anything extra.
Any ram above 1600 should have a setting called XMP, you simply enable this and the ram will run at its rated speed (if you have an intel rig) if you have amd, there is usually something called xmp or DOCP, enable this, and then sometimes a few more tweaks are required. AMD is well behind in its memory controllers, so sometimes voltage tweaks are required.