You got it wrong. I was there that night, in 1972, at the Palladium photographing Black Oak Arkansas (on assignment for their record company, if I recall) along with John Mayall and Chuck Berry.
I don’t believe anyone actually invited the Stones. But Mick Jagger, Mick Taylor, and Keith showed up backstage. (They were playing a gig at the LA Forum in Inglewood.) Keith came out on stage and plugged in. But, yes, after a few tunes Chuck did tell him something to the effect that there was room on that stage for only one guitar player who sounded like Chuck Berry. Richard (no “s” in those days) did leave. But, as everyone knows, they later became fast friends. And clean-shaven Keith Richards, wearing a backup-man’s suit, played rhythm guitar with Chuck Berry for quite a number of concerts.