Back in the 50s, "singers" would make "public appearances" where they lip synched to their records as well.
Link Wray spills the beans in this clip (he played guitar instrumentals).
Link Wray tells the story behind his hit "Rumble"
And some of you may be scratching your head asking "Who's Link Wray" (the so-called experts at the Rock and Roll Hall of Fame did this year) but here's one Mr. Jimmy Page showing off one of his favorite records in a documentary that should've just consisted of the hours of him playing records for the filmmakers.
Jimmy Page listens to Link Wray's 1958 Power Chord/Distortion Classic called Rumble
They may have occasionally lip synched, but there was no auto-tune so they had to have the goods