I have a very similar system to you.
To answer your question, no. You don't need to change any memory frequencies if you don't want to. It won't affect your cpu overclocking.
To overclock your cpu, you just need to increase the multiplier and cpu voltage. None of this will affect your memory or require any changes to the memory frequency.
However if your memory kit is xmp ready, you should enable the xmp profile to have your memory running at factory overclocked speeds.