New York State Pavilion from October 15, 1977. In the center you can see OZ and other props, see detail in this gallery.
An extreme blow-up shows the OZ of WIZ, October 15, 1977.
I didn't realize it at the time but this detail from http://SWC-Biogon.smugmug.com/photos/191494492_f6Bgc-L-2.jpg shows the "OZ" prop, scene graffiti and the set crew moving a taxi prop. It wasn't until years later, when I picked up a DVD of the WIZ that I took a closer look. October 15, 1977.