No - 6.5 you can edit all the forums in one handy little chart. That's one of the main reasons to upgrade.
Control Panel-> Group Management -> Group Accees (tab) Check your groups at the top - and then you'll see a chart where you can overview everyone's access. (Example, check the guest button at the top and make sure they are all set to no access).
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That's one of the main reasons to upgrade. 
