Depends on how you define overclocking. The modules are definitely not overclocked, because the are sold this way.
The motherboard (well, the ultimately CPU-integrated memory controller) might have to operate outside its specified range. This may or may not be harmful.
Slightly OT: Faster memory usually won’t get you anywhere. More memory will.
Update:
Your CPU, an i7-4790K, supports up to DDR3-1600 as per specifications. With XMP active, it probably won’t have any problem going higher. For example, I’m using an i5-2500K (albeit at 4 GHz), which is officially maxed at DDR3-1333, at DDR3-1600. I have been from the start (well over 3 years ago) and never encountered any problems.
Your motherboard, the Sabertooth Z98 Mk I, is rated for DDR3-1866. This may or may not limit—my board is rated for DDR3-2133. (Not that there’s any CPU supporting this, heh.)