This worked for me (PC only don't have PS3) so I think its a good indicator if you are ready or not.

PC:

Credit to Althurd for finding this out.
Ok, seems like the Launcher has been updated to reflect this. When I login with my account with a EA code applied, it just gives me the "Hey, wait till early access to play" Message. However when I try to login with a different account with no EA code applied, I get this: No valid or active service account is available to play FINAL FANTASY XIV: A Realm Reborn. Proper registration through the FINAL FANTASY XIV: Mog Station is required. Users participating in early access must also complete registration by August 30, 2013. Using the code enclosed with your package, please complete registration through the FINAL FANTASY XIV: Mog Station. So trying to go through the launcher and see if gives you an error.


PS3

On your PS3 XMB(Xross Media Bar–that's your main PS3 system menu):
Go to "PlayStation Network" > "Account Management" > "Transaction Management" > "Services List"
You should see FFXIV:ARR in the list.
Press X on FFXIV:ARR and you should see "Final Fantasy XIV: A Realm Reborn Early Access" on your PSN account.
That is it. You can rest assured that you have Early Access on PS3. You do not have to re-download the game client again if you have already downloaded it for the open beta (beta phase 4). It is the exact same file on PSN. (You can test this by going into your PlayStation Store, choose "View Downloads"[on the bottom left hand side, just keep pressing down on your d-pad]. You will see that you only have one FFXIV:ARR in your download list [both from open beta and early access codes] instead of 2 separate items.)