Looking through the notes I have compiled from a myriad of websites, I am aware of at least five episodes (possibly six, as RJSchex notes) that exist in some form:
-The two held by the Paley Center are June 11 and July 4, 1975, the former being a master copy (more specifically, per the listing, show #258) and the latter having been recorded by Andy Warhol. The former is also rather noteworthy for co-host Ruta Lee being hit in the head by a falling chandelier.
-Regarding the other three, they are held by
Archival Television Audio, Inc. (as audio recordings, per the company title): the debut show (July 1, 1974); October 15, 1974; and July 15, 1975.
clips from a third—from the final seven weeks, using the "Face Lifters" format—can be seen on YouTube in the "March of the Game Show Hosts" video.
Which per my notes is from the 1983 Daytime Emmy Awards, among a variety of other game show clips.