Hi! I write from Italy, so please forgive me for my macaronic English, whenever that is the case. In Italy we have very rare magazines: here are two interesting pieces containing Barks' Darkest Africa in its original edition. I think that recent American editions of the story were based on these Italian editions (the magazines are almost identical except for the cover):
Apart from these two, the book generally considered the rarest in all Italian publications is undoubtely this one: inducks.org/issue.php?c=it%2FANA+++1
This is considered the first ever "true" Italian comic book, presenting a story in its entirety. Topolino and all the other popular comic magazines of the times were still published in newspaper format, with very few, big size pages, and with miscellaneous material inside.
This was a somewhat pocket issue (Albo, in Italian), presenting a single story from start to finish.
Only ten copies of the original 1933 edition of this are presumed to exist.
Oh, and... judging by that very clumsy-looking drawing of the Three Pigs on the cover of the 1936 French edition, I have to assume it's either redrawn or an original drawing done especially for that version. I wonder how the drawings inside look.