I hate it when an issue is resolved, but the loop is never closed on the forum, so here we go...
Through significant effort and a lot of good fortune, I now know the entire life history of this car with the exception of details from the 6 years between '98 and '04. I know was that after leaving television it was with one family in Vegas from '70 to '98, was sold and taken back to Los Angeles from '98 to '04, was sold and taken to Chicago from '04 to '12, and basically to me in SC from there. Fortunately it's only been with a few owners, has been well cared for, and has spent most of its life in a nice, dry place. Thanks to all for the research ideas!