No, Special:Deadendpages is a list of pages which contain no outgoing links, i.e. are "dead ends" - Special:Lonelypages is a list of pages with no incoming links.
That's certainly how it should be, but it doesn't seem to be how it is. Take a look at http://www.thecatholicwiki.com/wiki/Special:Deadendpages, there are plenty of pages on that list with links in them, and it's not just a caching issue, either - the links have been there since the articles were created.