Ah yes, the factory tent...
Saw one of those this past summer here in Ontario on a 1976 Chevy Nova SS hatchback. I talked to the owners, and they said it was only offered for one or two years and that not many were sold. Didn't know they sold them on the Pontiac Astre as well.
Wouldn't dare suggest how many are left, it would likely be discarded relatively soon into ownership.