True, but that is only a matter of definition. The geographic definition of the eastern hemisphere is from 0-180 degrees longitude measured in an easterly direction from Greenwich. Since Attu Island is only 172 degrees, it is in the western hemisphere according to geographic definition rather than the political one which is shifted to result in better separation of Asia and North America.
Not that I knew any of this before you brought up the idea. Duck Duck Go (google equivalent) is such a fine thing.