Bob Dylan 12 Metal Acetate Master Recordings 4 Track Tombstone Blues

Excellent condition Metal acetate contains 4 tracks,2 per side. One side label In crayon and on sleeve are numbers Co 86838 2. Also on sleeve is reference Bob Johnson.Former owner had a small piece of paper with 4 titles written,3 Tombstone Blues,1 Positively 4th St. Hard for me to read his writing so I took a pic and added to site. I have not played to check as I no longer have a stereo system. Maybe a Dylan collector can look at titles and date this. Judging by zip code on envelope it is newer than 1964. When I googled the numbers Tombstone Blues with It Takes A Lot To Laugh .