hkp, Four Color 318 has one of my favorite duck covers and your copy is one of the best I've seen. Nice.
Since some people may not be familiar with the Barks March of Comics, I'll give a little background. A lot of collectors aren't familiar with these comic books because they are seldom offered for sale and Overstreet moved them out of the comic book section into the "Promotional" section of the guide.
March of Comics nos. 4, 20 and 41 each contain a full length original Barks story. They are among his best works. No. 20, which I posted yesterday has the story "Darkest Africa," which has never been reprinted by Disney because it contains exagerated racial stereotypes. Two other March of Comics issues, nos. 56 and 69, also have Barks art, but do not have complete Barks stories like the others.
These books are considered by some collectors to be the hardest Barks books to find. Also, because the covers are made of cheap pulp, they are rarely found in fine or better condition. In the 1990's, Geppi and Snyder placed a full page ad in the Comic Book Marketplace offering to pay over guide for any copies of nos. 4, 20 or 41.
Here's no. 41, which has the classic story "Race to the South Seas":