If its copper, good chance its split. Theres not much expansion to copper, but i have saw it freeze and not split.
Once its thawed you will have a little mess if the water is not on. If the water is on, big mess. But like they say, you gotta break eggs to make breakfast. You gotta turn it back on eventually. Unless you can see the pipes clearly, just using it will be the only way to get your answer.