[Plugin: Custom Post Type UI] When I'm done creating the new post types, can I deactivate the p

If you disable the plugin the custom post types will no longer be registered in WordPress. All of your CPT content will still be in the database, but WP won’t know what it is.

You can always use the Get Code feature, which generates the PHP code to register your CPT in a plugin or functions.php. The next version has an easier way to get this code 😉