unregistered

My forum is locked down to members only, so if you are unregistered or a SE bot, you can see the forum thread titles listed, but clicking on a thread takes you to a login page. Which is ok because I do not want unregistered users to read a thread, but this also totally kills search engine...

how can i allow unregistered users to see upgrade page? https://site.com/account/upgrades

How do I disable the option to select a different style for the Unregistered / Not logged in usergroup? I don't see this as a permissions option on the permissions list. Thanks