I can't find any record of what USPS method the customer chose on invoices, packing slips, in Super Orders. It just says "United States Postal Service."
My client is back calculating the amount added to the order and, I think, re-inputting the weight at USPS.com to determine if the purchaser chose Priority or Media mail (if a US domestic order). Are we both missing some obvious place where we'd see, say, "PRIORITY" "FIRST CLASS" or "MEDIA" shown?
The date stamp looks right for the Nov 2007 updated module ... I don't know if you had customizations to your site, however as I am not seeing a simple way to remove the method without customizing the code ...
Have you tried to compare the file:
/includes/modules/shipping/usps.php
Beyond Compare reports a match on usps.php from server and from USPS_NOV192007.zip.
I attached a gif (which I've never done here before, hope it works) of at least one place where I imagine "Priority", "Media" or "First Class" would be displayed. It sounds like it's expected on your end, too, rather than a new request, right?