Possible Bug in testing if WP_Rollback class exists

I was reviewing the WP Rollback source to see how I might use it to rollback beta versions of my plugin if the site doesn’t have the WP Rollback plugin installed and I see what appears to me to be a bug. It’s probably not an issue because the plugin code is only being called once by WordPress but it still may be worth correcting.

File: wp-rollback.php

Code:

if ( ! class_exists( 'WP Rollback' ) ) : {

	/**
	 * Class WP_Rollback
	 */
	final class WP_Rollback {

Shouldn’t the first line above have an underscore in the class name. I.e. it should be:

if ( ! class_exists( 'WP_Rollback' ) ) : {