Of course. Everything Apple can keep/control there in Cupertino - software, services, OS-related tidbits - will be more secret. The leaks are almost always from their hardware partners (iPhone frames, chassis, monitor sizes/specs, some new iPad size, camera placement, etc.).
Other than executing a bunch of suppliers and factory workers in Asia (and perhaps a few American and UK journalists and bloggers) on a fairly ongoing basis, I don’t know how that gets stopped/addressed.
For the record, I don’t think it needs to come to that, of course. Just want to make that clear.