My Son (born 2003) Had Twinrix Junior. First Two Doses

My son (born 2003) had twinrix junior. First two doses delivered on schedule in December 2007 and January 2008. 3rd dose not until 2 years later, January 2010 Now (October 2015) he is being offered a Hep B vaccine as part of a school program. Should he take this. Is the Twinrix Jr no good because of the late 3rd dose? Is it safe to take the Hep B vaccine anyway?