It's A Blues Thing (1968)

1. Eleanor Rigby
2. Let's Go Get Stoned
3. Crying Time
4. You Are My Sunshine
5. Esther Phillips guest medley: Monolog / You Must Be Crazy / Long John Blues / Jelly Jelly Jelly 
6. A Girl I Used To Know
7. Ode To Billy Joe (With Clydie King)
8. I Won't Leave

Album Live CD: Monad B000003J7X, 1968 (1995).

The liner notes of this semi-bootleg from 1995 don't offer any information on the location or date of the concert.
Looking at the setlist, and - most notably - listening to Billy Preston's organ playing, this live concert was probably recorded in 1967 or 1968*. Ode To Billy Joe is an excellent track, with Clydie King, who also put it on a single.
The 15:29 medley by Esther Phillips is a pain in the ear. I doubt if this actually was even taped at one of Ray's shows.

The very similar contents of the Bakersfield concert, make (the Summer of) 1968 the most probable year for the Blues Thing show.

And this review of the Schaefer Music Festival concert on July 7, 1968 confirms the year and the season once more:

from Cashbox, Jul. 20. 

#7 (Ode To Billie Joe) was also released as part of Clydie King's compilation album The Imperial & Minit Years, Stateside EMI 5099950958122, 2007.