If you are using the altestn SeasonPass then the FC logo will tell you it is JB. Earlier release did not have this visual cude.
If you apper to be going through the JB process and an apparently successful restore is not putting the FC logo in the bottom right, then the chances are that you restored the wrong .ipsw file. The JB one that SeasonPass generates will always have _SP as part of the filename. You can manually select the .ipsw file to be restored by using SHIFT (Option on Mac)+Click on the Restore button. This will put up a file dialog to allow you to select the file to be restored. Note, however, that you need to be in DFU mode or the restore will fail.