Hyphenated serial numbers are always impressed into back of headstock. 1965 to 1972 Serial Numbers. Number on back of peghead, no hyphen in number. July 1972, 84th instrument. 1973 to 1981 Serial numbers.
Hyphenated number is impressed into back of peghead.
November 1974, 252nd instrument. The year is the first Letter, The month is the second letter. The year is the number after the letter-The letter is the month.