It looks like the the templates act as linked documents - you can move them around in the library, and you can rename them, but it is still that template that is used when you publish.
So my question becomes - where is that document linked and can you change that link?
If you can't then the published guidance is NOT clear or accurate. What you would need to do is:
1. Copy the template to create a backup
2. Rename the ORIGINAL
3. Modify the ORIGINAL
If anyone can clarify that'd be fantastic!
Actually, if you go into the source file for the Question (in the Local Repository) then you will find a statement:<QuestionTemplate>0a9ee099-ee19-4bbf-b14b-7efefcc119d4</QuestionTemplate>. You could always manually change this. i wouldn't recommend it, but it does at least show that the functionality is theoreticaly there...