The eyes of Dewey's costume are only shown as holes throughout most of the short until the very last shot of the nephews waving goodbye to Witch Hazel, then his eyes are shown peeking through the holes.
When Huey, Dewey and Louie are first seen walking up to Donald's house, Dewey is not holding a bag like the other two, but when they get on the porch, he has one in his hands.