Here's another site (NRA Museum)- Shows a listing of serial numbers used by Browning.
http://www.nramuseum.org/media/94094...anufacture.pdf
BOLT ACTION RIFLES
(Safari, Medallion, & Olympian Models)
YEAR SER . # CODE
1959 - N/A
1962 No prefix (numeral-letter) before Ser. No.
(i.e., only digits)
1963 3-single letter prefix or suffix by Ser. No.
1964 4-single letter prefix or suffix by Ser. No.
1965 5-single letter prefix or suffix by Ser. No.
1966 6-single letter prefix or suffix by Ser. No.
1967 7-single letter prefix or suffix by Ser. No.
1968 8-single letter prefix or suffix by Ser. No.
1969 Single letter (Y, Z, or L) followed by
last 2 digits of year of mfg. Prefix only.
1970 “Y70" prefix
1971 “L71" prefix
1972 “Z72" prefix
1973 “Y73" prefix
1974 “Z74" prefix
1975 “L75" prefix