Serial Number        Year Manufactured
        1                         1876
        700                     1877
        1700                    1878
        3000                    1879
        5000                    1880
        6000                    1881
        7000                    1882
        8000                    1883
        9000                    1884
        10,500                 1885
        12,000                 1886
        13,000                 1887
        14,000                 1888
        16,500                 1889
        18,000                 1890
        20,000                 1891
        22,500                 1892
        25,000                 1893
        27,500                 1894
        29,000                 1895
        34,000                 1896
        40,000                 1897
        46,700                 1898
        52,000                 1899
        58,000                 1900
        66,700                 1901
        71,000                 1902
        76,000                 1903
        82,000                 1904
        88,000                 1905
        94,000                 1906
        100,000               1907
        106,000               1908
        111,000               1909
        116,000               1910
        121,000               1911
        126,000               1912
        130,150               1913
        132,400               1914
        137,000               1915
        142,575               1916
        146,600               1917
        155,000               1918
        165,900               1919
        169,500               1920
        175,500               1921
        190,450               1922
        198,475               1923
        206,700               1924
        219,850               1925
        230,900               1926
        239,500               1927
        252,900               1928
        263,200               1929
        273,700               1930
        280,130               1931
        281,360               1932
        289,743               1933
        294,687               1934
        300,690               1935
        307,996               1936
        315,575               1937
        322,650               1938
        324,859               1939
        327,850               1940
        338,500               1941
        348,150               1942
        354,600               1943
        355,500               1944
        355,750               1945
        355,850               1946
        366,650               1947
        376,100               1948
        383,650               1949
        389,600               1950
        396,300               1951
        393,301               1952
        420,057               1953
        427,301               1954
        500,001               1955
        571,850               1956
        652002                1957
        718,626               1958
        779,657               1959
        834,200               1960
        898,556               1961
        949,465               1962
        C00501                1963
        C73854                1964
        E54106                1965
        H31247                1966
        K35274                1967
        L20454                1968
        "M" prefix            1969
        "N" prefix            1970
        "P" prefix             1971
        "R" prefix             1972
        GA30000               1973
        GA40000               1974
        GA50000               1975
        GA60000               1976
        GA70000               1977
        GA80000               1978
        GA90000               1979
        HA00000               1980
        HA16500               1981
        HA23431               1982
        HA33389               1983
        HA45522               1984
        HA58992               1985
        HA68842               1986
        HA76618               1987
Starting in 1987, the two-digit prefix number plus 50 will give you the year of manufacture on all Conn products.

During the years from 1965 to 1969 information is more inacurate.  There was a fire in the Indiana facility where some information was lost.

In March of 1974 an alpha-numeric system was established where the first character (letter) of a serial number indicated the decade; "G" for the 1970's, "H" for the 1980's, etc. The second character, also a letter, indicates the month of the year; "A" for January, "B" for February, "C" for March, etc. The third character (a number) indicates the number of year within the decade (indicated earlier by the first letter). The fourth character (number) indicates the specific type of instrument: "1" = Cornet, "2" = Trumpet, "3" = Alto Horn, "4" = French Horn, "5" = Mellophone, "6" = Valve Trombone, "7" = Slide Trombone, "8" = Baritone Horn & Euphonium, "9" = Tuba, and "10" = Sousaphone. The remaining four numbers of the serial number indicate the production number of the instrument on a monthly basis.