Here is some serial number related info that Chip had posted on the original T-60 forum quite some time ago. I don't believe that I've posted it here yet.
During the last few years, I have received more than a few T-60s that were the very first ones made on the gunstock carving machine and the Ekstrom-Carlson router, before production was even in sight. The sequence of markings on the first ones was;
CT-1, CT-2, CT-B, the first three built in my carport for the 1976 NAMM show. They were in order, 6 keys per side, 3 keys per side, and the bass. These were hand-stamped.
The next ones were:
Guitar Dept. 1, through Guitar Dept. 5 or 6.(1976) Hand-stamped
Then 0000000.0 through .00000000, 000000.0.0, and 00000.0.0.0 and these were the sales rep samples. Note that the decimal points progressed through the eight numerals and the last of the ten had two decimals. These would let us know and identify if any of the sales reps "lost" their sample. (late 1976 or early 1977)
There were some undisciplined zero-numbered ones with various single digit numbers included in the zeros, which went to artists like, Chet Atkins, Jerry Reed, Neal Diamond, Billy Gibbons, etc.( 1977)
I remember the "8Mxxxxxx"s, but am not sure where they were in the order, only that they weren't before the above and the #00245XXX which was the true first production guitar and was presented to Mississippi Music in Meridian, MS, (the store that Hartley's dad owned before retiring). The Schmidt Serial Numbering head didn't have the capability of letters, only numbers, so there would have been only a very few with the 8Mxxxxxx.
There were a few specials, like the Magnolia wood T-40 bass for Ken Achard, author of "The History and Development of the American Guitar" (with rear mounted pickups and controls), that were made, with Hartley's blessing, off the records and with their initials for serial numbers. hand-stamped
Charley Gressett, his wife, my wife, and I went to see Neal Diamond years later, in California, when we worked for Fender, and were appalled that he had red, white, and blue, NEON TUBES outlining the T-60 that he played when singing "Coming To America", (or something like that). That was probably his 000000XX.
"That's all I know about that".....F. Gump
Chip
It's humorous to read the word,"Vintage" after almost any guitar that's a decade or more old. The word has no meaning anymore. There are two T-60s on ebay now that have an 8Mxxxxxx E serial number. What's funny to me as they don't know that the "E" was stamped on guitars with blemishes and small mistakes and were only sold to employees at a good discount. Those are seconds or blems, not "Vintage" and special units. I do like the part about "rare", meaning we must have not made too many mistakes or they wouldn't be "rare"
Chip