I have changed over front struts a few times and there is normally there is nothing to adjust on a Z3. BMW do sell a camber correction bolt, so if you see an eccentric bolt in there or some washers between the two lower bolts and the hub then an adjustment has been made at some time. If not then you are good to go
That said. For piece of mind I would always get an alignment check after changing major suspension parts. Better that than killing a tire in a few hundred miles.