Hi all, I’m trying to confirm the authenticity and year of a Barney Kessel standard that I was told was a 1966. The sticker inside the f hole is missing and has M 5945 stamped in ink under the sticker. The headstock is a custom headstock with the Gibson logo that doesn’t have the dot above the “i” placing it in the early 70s I believe. The rest of the guitar are to standard specs. The headstock also has a 6 digit serial. Any help would be greatly appreciated!