The guide to naturalization has outdated information regarding the photograph style. The new passport style photo requirement has been used since more than 2 years ago.
http://www.uscis.gov/graphics/services/natz/index.htm
In particular, the informational flyer in that page says:
"Washington, DC — In accordance with language specified in the Border
Security Act of 2003, U.S. Citizenship and Immigration Services (USCIS)
announced a change in the photo requirements for all applicants from
a three-quarter face position to a standard, full-frontal face position to take
effect August 2, 2004.
USCIS will accept both three-quarter and full-frontal color photographs until
September 1, 2004, after which only full-frontal color will be accepted."
I haven't heard of people having had problems with the wrong information in the guide, but I would be curious to hear. It would be great if USCIS could update this document, but it is an unfortunate fact of life that sometimes documents get outdated and not made up to date.