If you go far enough (Black areas on the live map), you'll get to the unloaded chunks, which will become 1.7 terrain once reached and loaded.
If you go to an unexplored area (black on the livemap) in the frontier the generated terrain will be 1.7 terrain.
I got confused on what you meant, because a lot of people refer to 1.7.2 as 1.7, and the server is currently on 1.7.9, which is still in the 1.7 updates.