Yes, that's the whole database.
You can run Admin provisioning tool to make yourself the admin user again after restore. It's your dev system so I don't assume you need other users. If you do, you can import them.
If you want to migrate only partial data, then you must export/import via data entities. This can be very time consuming, and I don't think you should do that in a dev system. Your dev system should be disposable, and you should be able to set up a new one quickly by deploying new system from LCS, restoring db template and getting latest code from source control.
Your dev data template would usually come either from test system, or some centrally maintained golden config / golden dev data system.
Anyway all this is beyond your original question which was about migrating data from older version system to a newer version. You can do that via db backup or data entities.
