The difference in the authority versions features is that with the most current you can create users who cannot change their own credentials.
On the other hand, the values stored for all these rights are different among authority versions, and the newer version may not work if you decided to install an older version of Zenphoto that did not know of it.
So, as long as you are satisfied with the version of Zenphoto you are running you can upgrade the version of the aurhority if you want the new feature. But you do not need to do anything. At some point Zenphoto will upgrade the version when it no longer supports the older one.
As for your other problem, carefully look at the publish state of the items. That is probably where they are different.
If you want to see you gallery the way a normal user sees it use the `show_not_loggedin` plugin. But be aware. It does just what it says--makes it look like you are not logged in when you view the front-end of your gallery.