I know this is probably redundant to talk about since not many people really care about minor details to characters, but while looking through DOAWK through different languages I saw the Japanese version and I've noticed that they've added another finger on the characters in the Japanese version giving the characters 5 fingered hands.
Japanese:
Cabin Fever: http://diaryofawimpykid.childrens-library.com/images/Diary_Of_A_Wimpy_Kid_Cabin_Fever_0_large.jpg
Original:
American:
Cabin Fever: http://booksofglory.global2.vic.edu.au/files/2013/05/8242024_0_9999_lge_v1_m565775698387768041-1x2ht20.jpg
Original:
This is only done on the cover, they still have the standard four fingered hands when you read the book.
http://im8-a.mbokimg.dena.ne.jp/3/7/547/445963547.5.jpg
I think they changed the characters fingers so Japanese readers wouldn't view the characters as apart of some mafia. I know they've done this similar thing with Bob the Builder, Abe from Oddworld (Gave him 3 fingers), Fat Princess, and The Simpsons (on VHS and Videogame covers) when they were marketing them in Japan.