Ideally, on a stick shift car you want the nose closed. As your clutch wears, all the dust that is created flys around inside the bell housing. No issue in an auto, but the debris can enter the end of the nose and contribute to wearing out the bushing. Of course, even with the nose closed, the debris can enter from the other side, so I am not sure how much difference there would be long term in the real world.
Having said that, if you find an open nose that otherwise fits, it will work fine. That bushing is really easy to replace, and even easier on an open nose starter. I wouldn't hesitate to use an open nose for now, and keep a look out for the correct nose down the road. One will turn up.