Not according to Wikipedia, which quotes from Geoffrey Emerick, the engineer on the track:As mentioned, that was indeed a clave. But, that brought to mind a song I hadn't considered before... "Blackbird" by the Beatles (1968) has a metronome clicking away through the whole song! Hard to know if drums were ever intended, or if McCartney simply wanted the 'nome be the beat or sound like a foot tapping. It doesn't sound like it was first recorded on a separate track to just act as timekeeper (as it slightly bleeds through the guitar feed on the opposite channel, indicating that it and Paul were all recorded at once) but if it was done separately, it managed to leak through the phones. In any case, it's part of the song as we know and love it, and therefore pre-dates the others I had mentioned.
So, the current favorite would be Blackbird.
The tapping "has been incorrectly identified as a metronome in the past", according to engineer Geoff Emerick, who says it is actually the sound of Paul tapping his foot, which Emerick recalls as being mic'd up separately.