I can't remember right now, but there is a specific Key in the Registry that sets the Branch you are on.
Just an FYI remembering this entire ordeal last year with release 240, MS did not officially state it was GOLD. We figured it out by regedits as I have stated posted previously in this thread. On the official release date we all received a small KB update that changed our registry to reflect we were on the release version. And a few other day 1 updates that day. Anyhow I feel the need to point out zero day update is not the correct the term but day 1 update(s) is correct.
The Term RTM is no longer used anymore as windows 10 will never leave dev time and always been improved so instead lets make a new term RFD release from Development that means it was finished and released from the branch or RFB release from branch
It's always there providing you are an insider. Even if it was not there, once you check for updates it will appear.
That is fine. I think everyone gets an Applicability key once check for updates has been done either manually or automatically. Insiders will just have more information in that key.