SECURITY – wp-activate.php and wp-signup.php

I am running WP3.0 RC3 with the trunk version of Donncha’s domain mapping plugin and 4 separate blogs.

I want to lock down my install from spamming attempts. Is it safe to restrict access to wp-activate.php and wp-signup.php if I have no intention of opening my install up to blog signups? The only way I would ever create a new blog is from the Super Admin menu.

I already have wp-config.php restricted in my .htaccess file with the following code; can I safely do the same with wp-activate.php and wp-signup.php?

<files wp-config.php>
Order deny,allow
deny from all
</files>