Now way for the IBM card to prove who owned it, just that they produced it. It would prove how many were built, all the options, and which dealer it was sent to. With that date range of this 66 Belvedere, it would be easier to find it only have to search about two weeks of build records. Has anyone ever sent in for an IBM card and had Chrysler tell you they couldn't find it? I have not heard of it happening yet.