I asked the mods to move all the "first sale" posts to a new thread.
Like I said a few days ago, the "downstream" collectors like us clearly "own" our posters. I doubt there is a single case of a movie studio contesting ownership of a poster obtained by an individual collector from any source - dealer, other collector, theater employee, Ebay seller, etc. You don't see Universal claiming to own that Dracula poster that Heritage sold, do you?