You should be able to use DDR3 1600 just fine, but the board may not recognize or acknowledge the memory's registered 1600 timings. In other words, if you want 1600 speeds, you'll need to dial those in manually (i.e. set the FSB/memory ratio accordingly). Since you plan to overclock, you'll probably need to do this anyway.
The worst that will happen is that you have to run your DDR3-1600 memory modules at DDR3-1333 speeds.
Oh, one more thing, you might need to increase voltages to support the 1600 speed. Running memtest86+ will tell you when your settings are stable.