Wow! Thanks, Ed. I learned something new about Camaros today!
but we don't know what dealers sold them.
As far as dealers that sold them, there's a link in the Team Camaro thread you reference to a '69 Z/28 that was sold last year. The seller states the car has the original dealer invoice from 1969. That might be a start to finding the dealers who sold them if you (or someone?) contacts the seller (top_self_reps) or the buyer (zmachz).