U can use that book for serlet part, coz the difference between Servlet 2.4 and 2.3 specs is not that much, compared to the difference between JSP 2.0 and 1.2 specs...
But u may need to have a look on servlet 2.4 specification to make sure that all of the objectives are covered... Here is the link to the learning process to the new SCWCD exam... I hope it might help you...
http://www.jdiscuss.com/Enthuse/jsp/ViewPosts.jsp?forumid=26&topicid=785
Co-author of SCMAD Exam Guide, Author of JMADPlus
SCJP1.2, CCNA, SCWCD1.4, SCBCD1.3, SCMAD1.0, SCJA1.0, SCJP6.0