I have a 2006 Buick Rendezvous which we purchased used last year. This vehicle did not come with the optional the third row of seats. The question is can a third row be added if the vehicle didn't initially come from the factory with the third row already installed? I have purchased a used third row of seats from a junk yard and the seat belts. The issue is with the mounting points for the seat belts. All three mounting points exist, however instead of having welded nuts there is a hollow barrel. At first glance it looked threaded, but it is not.