If you need for any reason to remove an extension, ePO 5.3 give you an option to save all policies, task, etc. so you won't need to manually create them after re-install the extension or check-in the product.
On ePO 5.3 go to Menu -> Server setting -> Policy and Task Retention
You can choose if to save the tasks & policies or not.
The Virus Scan policies is exists, but you can't edit, rename or delete