Two of the 1963 images featured a mouse as a "brave" paddling a canoe and a mouse as a chief. In 1991, the paddling mouse was no longer an Indian and the mouse chief was gone.
A few points to consider:
1) No other race appears in outdated and stereotypical costumes in The Best Word Book Ever. Only Indians. As I've said before, Indians are the last US minority it's "safe" to stereotype.
2) Native stereotypes were as accepted then as other stereotypes--e.g., men had jobs while women kept homes. No one thought twice about them.
3) Twenty-eight years later, Scarry and his publisher have removed the stereotypes because they're clearly wrong. Most people today would say the gender stereotypes are wrong, but they still don't understand why the Native stereotypes are wrong.
4) The revision shows how easy it is to update and eliminate stereotypes. It doesn't harm the book's content, it improves it. The same thing happens whenever people eliminate stereotypes they claim they can't live without.
For more on the subject, see What's Wrong with Grizzly Bob? and I Isn't for Indians.
P.S. The Best Word Book Ever doesn't look like the best word book ever to me. It looks more like a very average word book.