This disc was auctioned on eBay in May 2004. The mix would most certainly be the standard stereo mix.
Since this is a U.S. acetate, the date 5/14/69
is probably May 14, 1969.
For recording history and further studio details see an Apple acetate - here
EXTREMELY RARE BELL 45 ACETATE
THE BALLAD OF JOHN AND YOKO & OLD BROWN SHOES
Item number: 3815186310
Starting bid: US $499.00
Time left: 5 days 10 hours
Ends May-17-04 20:46:33 PDT
Start time: May-10-04 20:46:33 PDT
History: 0 bids
Item location: San Francisco, CA.
United States /San Francisco
UP FOR AUCTION IS A RARE BELL ACETATE DATED 05/14/69. THE WORD Xelusive WAS WRITTEN BY AN UNKNOWN INDIVIDUAL ON THE LABEL SIDE OF "THE BALLAD OF JOHN & YOKO." THE FLIP SIDE PLAYS "OLD BROWN SHOE."
THE CONDITION IS MINT WITH
MINIMAL SURFACE SCRATCHES AND
A MINUTE NICK ON THE EDGE OF THE RECORD WHICH DOES NOT AFFECT
THE PLAYING OF THE ACETATE.