You have two options:
Create the widget yourself with the “new” widget api as a class an it will be multiple instance widget.
Or find the line that registers the widget and register the same widget with a new name for example find:
register_sidebar_widget(array('Content License', 'widgets'), 'widget_cc');
and replace with:
register_sidebar_widget(array('Content License 1', 'widgets'), 'widget_cc');
register_sidebar_widget(array('Content License 2', 'widgets'), 'widget_cc');
register_sidebar_widget(array('Content License 3', 'widgets'), 'widget_cc');
register_sidebar_widget(array('Content License 4', 'widgets'), 'widget_cc');