The song "Not Guilty" was written by George Harrison and was meant to be featured on the upcoming new LP (eventually entitled "The Beatles" (White Album)". This was not the case as in the end the song was left in the can, as it were.
There was a lot of work put into the basic track of the song including the musical stylings of George on guitar, Ringo on drums, Paul on bass and Chris Thomas on harpsichord. At this point of time and until the end of the Beatles' career, John Lennon rarely played on a George Harrison track for some reason we will never know.
Recording the basic track took two nights to complete; the first evening was on August 07 1968 with 46 takes and the next evening August 08 1968 with a further 51 takes. The take used for the commercial recording was take 97 and four track reduction took place taking the song to take 101!
On August 09 1968, there were overdubs by George of more guitar and also some added drums by Ringo. Finally, on August 12 1968, George Harrison added vocals to the song with one pass using John and Paul to add harmonies but this was discarded and it ends up being a solo vocal performance.
A mono mix of the song was completed on August 12 as well and you can hear this version on various bootlegs including the vinyl versions of "Not Guilty" and "Nothing Is Real" as well as the CD version of "Unsurpassed Masters Vol. 04".
A stereo mix was created by Geoff Emerick in 1984 especially for the aborted "Sessions" LP and it is the same mix used for the Apple 3-LP/2CD "Anthology 3" project. Lots of phasing in the drums and vocals on this mix, plus a lot of editing.
Here's the original mono remix 1: