Thanks for the link to the specification section for Methods. It cleared my doubt. About the last sentence that you are referring to in the specification section is followed by “However, a function declared this way is not a method.” So the wording “argument list” makes no sense either way.
I come from Java background and I am finding, the syntax in Go particularly when it comes to creation and use of user defined types and interfaces is not really explicit.
Let me see if my view changes after gaining more familiarity with this language.