Brass players live in a world of plain numbers. Woodwind players do not: several of the most sought makers never used a pure numeric sequence, and a lookup that strips the letters throws the date away.
Lorée: the letters are the date
An F. Lorée oboe number like AL45 or FL03 is a letter code with digits that barely matter. The letters advance slowly — A opens in 1881, O marks 1900, BA 1959, FL 1981 — and the published chart has gaps, especially in 1959–1980. An unlisted letter can only be bracketed between its neighbours, and the archive says exactly that instead of inventing a year.
Heckel CREST: the date inside the string
A Heckel CREST bassoon carries a string like HC 120503: the last four digits are the month and year of production — 05/03 → May 2003. The archive parses the string directly and shows the documented records nearest your serial as corroboration.
Conn 1963–72: a letter is a block counter
Conn woodwind serials of this decade start with a letter — c00501 = 1963, c73854 = 1964, e54106 = 1965. The letters are block counters, not year letters: d, f, g, i, j, o and q never appear, and one letter can span two years, so the year needs the letter and the number. Outside this window the same field is numeric again.
Armstrong and Artley: prefix plus 50
From the 1970s these Elkhart makers printed the date in the prefix: 33-42562 means prefix 33 + 50 = 83 → 1983. Earlier prefixes are letter blocks (Armstrong's A/B/C = 1965). Keep the dash when you enter the number — the decoder reads it.
Buffet: the letter is part of the number
Early Buffet clarinets (1885 into the 1930s) carry a letter suffix — 408A, 1B — where the letter marks a multi-year block of the chart. The suffix narrows the date; the number finishes the job.
Why the archive keeps them apart
Every code system has its own confidence level and its own source. Letter codes read from a 1997 snapshot of a dealer page are honest reported data; Conn's letter table is official. The result card shows which is which — because "the letter BA means 1959–1967, per a chart last published in 1997" is a different kind of answer than "1954, per the maker's own table", and you deserve to know which one you got.