In the last section talking about improvements to reduce storage, couldn't the indexes be completely left out? Just storing the chain-end number in an array and

In the last section talking about improvements to reduce storage, couldn't the indexes be completely left out? Just storing the chain-end number in an array and using the array's index as the starting number. Edit: this article is from 11/12/2006 and the last section from 04/09/2009 according the the website's home page.