I think the confusion comes from the existence of two different but similar sites. The GGCA website is www.germanguns.com. click on "online store", then "club merchandise" and you should be able to find the slings. The site Larry Schuknect runs is www.germanhuntingguns.com. This site is more for information and history and was founded by the founder of the GGCA, consequently the similarity. Larry is a good guy and is part of the GGCA, so he may "hook you up", if he can't go to the GGCA site.
Mike