I can't recall seeing them do too many tunes from Bare Trees during the Buckingham-Nicks years, but here's Spare Me A Little... from 1975. In the last few frames there's a good look at John and #73-27. (I'm lookin' at you, Keith!) It's up nice in the mix, sounds like he had the bridge pickup Q-boosted and opened up.
And following up, here is the same number, from a couple months before. I think this is very late in 1974, Bare Trees tour with Bob Welch and Doug Graves in the band. #73-27 was wearing black pickups, its original bar tailpiece, and had yet to be fitted with a master volume. The groove within the band, to say nothing of the harmony parts is strikingly different from the '75 issue.
*I'm fairly sure this still picture is from the same show... see John's black Fender Precision in the stand next to his rig there?