The story published in USA was a little different.
"Finally, the two brothers collaborated on a neatly typed letter stating that one of them was a high school art teacher who was planning a class that would include a discussion of comic art, specifically Disney comic art. In particular, the “teacher” wanted to write to the artist who had been doing the Disney Duck stories for the last 15 years to ask about the technical side of writing and drawing comics.
A woman at editorial in Disney wrote back with the name and address of Carl Barks. John Spicer wrote a letter to Barks on April 11, 1960. Since it was the first real fan letter Barks had received, he was suspicious about it. Finally, Barks wrote back."