This is what I was lead to believe. The information is from March 2001:
The travel agency Hapag-Lloyd offers a guided tour. The admission charge is DM 20 for adults and DM 10 for pupils and students. The guided tours are held in Hamburg-Finkenwerder from Tuesday to Friday at 9:00, 9:30, 10:00, 11:00, and 11:30 respectively and take about two hours.
Mrs. Manuela Esch