Preferred domains - site: results and GWT preference don't agree

[Right Reading]

I wonder if anyone else has seen this and might be able to point me to an answer. I have a site that launched 21 November for which, according to Google Webmaster Tools, I set the preferred doman as www.sitename.com back on Nov. 23. But when I do a site operator search (today, Jan. 7) it finds only 3 results -- the home page, a wordpress login page, and a wordpress lost password page -- with www included (site:www.sitename.com), whereas it shows a substantial number of results with www omitted (site:sitename.com). Why might this be?

[tedster]

Note this sentence from within that Webmaster Tools section:

Once you specify your preference here, it may take some time for changes to be reflected in our index. While Google doesn't guarantee that we'll show your URLs in the form that you prefer, we will use your choice as a suggestion to improve our indexing.

If you want to be 100% certain, you should install a 301 redirect from the "no-www" form to the "with-www" form of your urls.

The details on how to do that will be specific to the server you are using. There's a good thread covering many of these issues in the Hot Topics area [webmasterworld.com], which is always pinned to the top of this forum's index page:

Why Does Google Treat "www" & "no-www" As Different? [webmasterworld.com]