Presuming you already copied all these files:
/includes/templates/classic/

to here:
/includes/templates/lock/



Open this file on your computer:
/includes/templates/classic/template_info.php

Edit to reflect your custom Template
i.e. $template_name = 'lock';

Upload to:
/includes/templates/lock/template_info.php


This will allow Zen Cart to know what the other Template is called and refer to it by name. Thus any files/folders you customize for your 'lock' Template should show as well.