No way to know for sure at the moment. Graphics have changed, and there might be some new terrain types in Civ4Col. I don't think you'll be able to just copy&paste a Civ4 map and run it in Colonization just like that.
Besides, remember that basically all resources are new. I don't know how Civ4Col would interpret a hill with uranium, a jungle with bananas, plains with game or an ocean square with an oil source. Same thing viceversa, as Civ4 wouldn't understand cotton, furs nor tobacco, among others.