Yvonne Elliman, Carl Anderson and Tim Rice of Jesus Christ Superstar fame. They looked real and still look real to me when I first ran across them many years ago.
The Elliman certainly looks OK compared to something she signed at a Zurich night club back in around 1973. "Sylvia" was either the manager of the club or someone who looked after visiting celebrities. Here is is:
To be honest I doubt very much that these are the kind of people that get forged much.