The fine folks at Periscope Films posted a 1980 film about the history of the Pan Pacific Auditorium....and I mean WAAAAAAY back into Pan Pacific history before there was a Pan Pacific. The film is a proposal for redevelopment for the PP and the area around it.
There is no mention of Xanadu but I suspect you MIGHT recognize the graffities on the front doors. Read the YT video description for further details.
BTW, the sound track goes dead during the mid-section due to, we suspect, YT's copyright mall-cops.
Watch the video HERE.
Don-O