yes, there definately are repeats of the same maps.
It usually helps for knowing where the other civs are. Sometimes the artifacts aren't in the same places, as the number of artifacts in any given game can vary. But, for the most part, the map will be the same, with maybe barbs, huts, and artifacts either being in the spots they were or not.
I recognize almost half the maps now.
The maps that are easiest for me to dominate are the ones I see on Game of the Week previously, and then get that same map on MP. Since in GOTW, you play the map over and over again, till you know the map by heart, it makes it so much easier to know where to go.