Previously un-documented as a surviving piece of original Carl Barks art; the cover to WDC 321 just surfaced!
The owner, Robert Wiener, wrote the following on his comicartfans.com page where he posted the art: "Carl Barks cover to Walt Disney's Comics &
Stories #321, April 1967. I got this from Don Phelps in the 1970's in
trade for a copy of "Donald Duck Tells About Kites". At the time they
were equivalent in value but I think I made the better deal. (I thought
so at the time.) I hadn't seen it for 25 years and found it last week
when looking for something else. Long story!"
Robert sure made the better deal ...