I Believe that is Williams Silver ZL-1 pictured in the background on the Used Car lot,as he just recently posted a Picture of it in one of these forums.
I read this also on another Website,and Saw that auction too.I have the entire April 1971 Salesmans Communication Kit that Filmstrip came in,and always thought that was someones car in the Background.
I was Glad to see it was someone from here.
Rick