The following list of numbers represents the date of manufacture followed by the piano serial numbers. The letters ‘sn’ mean serial number.
Piano Manufacturer: Kurtzmann
1900 sn-13000 1917 sn-61000 1925 sn-86000 1933 sn-97000
1905 sn-25000 1918 sn-65000 1926 sn-89000 1934 sn-97300
1914 sn-46000 1922 sn-77000 1930 sn-96000 1938 sn-107000
Piano Manufacturer: Lancaster
1956 sn-160000 1959 sn-169000 1962 sn-180000 1965 sn-191000
1957 sn-163100 1960 sn-172000 1963 sn-183000 1966 sn-195000
1958 sn-166000 1961 sn-176000 1964 sn-187000
Piano Manufacturer: Laughead, Gordon
1948 sn-4100 1952 sn-7500 1955 sn-9500 1959 sn-13800
1949 sn-5000 1953 sn-8200 1956 sn-10100 1960 sn-15000
1950 sn-5900 1954 sn-8900 1957 sn-10960 1964 sn-22130
Piano Manufacturer: Lesage (Canadian Affiltate sn- Aeolian)
1960 sn-36000 1967 sn-47000 1975 sn-56500 1982 sn-65800
1961 sn-37050 1968 sn-48000 1976 sn-58000 1983 sn-66300
1962 sn-38600 1969 sn-49500 1977 sn-60000 1984 sn-66750
1963 sn-40300 1970 sn-50500 1978 sn-61200 1985 sn-67300
1964 sn-42000 1971 sn-51500 1979 sn-62700 1986 sn-67730
1965 sn-44000 1972 sn-53000 1980 sn-64000 1987 sn-67905
1966 sn-45500 1974 sn-54500 1981 sn-65500 1988 sn-70000
Piano Manufacturer: Lessing
1900 sn-23090 1913 sn-56000 1917 sn-109500 1924 sn-171000
1910 sn-39000 1915 sn-90000 1918 sn-118000 1925 sn-180000
1911 sn-47000 1916 sn-99500 1919 sn-127000 1927 sn-196000
Piano Manufacturer: Lester (Betsy Ross)
1948 sn-175000 1951 sn-209000 1954 sn-241000 1958 sn-299700
1949 sn-181000 1952 sn-220000 1956 sn-272000 1959 sn-308800
1950 sn-193000 1953 sn-231000 1957 sn-280000 1960 sn-324400
Piano Manufacturer: Love, Malcolm
1956 sn-160000 1959 sn-169000 1962 sn-180000 1965 sn-191000
1957 sn-163100 1960 sn-172000 1963 sn-183000 1966 sn-191800
1958 sn-166000 1961 sn-176000 1964 sn-187000 1967 sn-191950
Piano Manufacturer: Lowrey
1963 sn-349000 1967 sn-449000 1971 sn-463000 1975 sn-519000
1964 sn-364000 1968 sn-421000 1972 sn-477000 1976 sn-533000
1965 sn-379000 1969 sn-435000 1973 sn-491000 1977 sn-528325
1966 sn-393000 1970 sn-449000 1974 sn-505000 1978 sn-541325
Piano Manufacturer: Marshall & Wendell
1900 sn-26500 1930 sn-111000 1938 sn-128500 1948 sn-137900
1910 sn-43700 1934 sn-118000 1940 sn-132900 1950 sn-138020
1915 sn-52600 1935 sn-120900 1941 sn-113510 1951 sn-138090
1920 sn-63200 1936 sn-123600 1942 sn-137300 1952 sn-138104
1925 sn-10620 1937 sn-126100 1947 sn-137800 1953 sn-138130
Piano Manufacturer: Mason & Hamlin
1900 sn-11800 1947 sn-53500 1965 sn-69100 1974 sn-77493
1910 sn-19100 1948 sn-55000 1966 sn-69949 1975 sn-78730
1915 sn-24000 1950 sn-57800 1967 sn-71006 1976 sn-80019
1920 sn-29000 1955 sn-61800 1968 sn-71994 1977 sn-81100
1925 sn-32700 1960 sn-65200 1969 sn-72945 1978 sn-82731
1930 sn-39600 1961 sn-66016 1970 sn-74263 1979 sn-84184
1935 sn-42500 1962 sn-66604 1971 sn-74791 1980 sn-85853
1940 sn-48000 1963 sn-67478 1972 sn-75534 1981 sn-87013
1946 sn-53000 1964 sn-68309 1973 sn-76447 1982 sn-87013
Piano Manufacturer: Mason & Risch
1900 sn-20000 1940 sn-57300 1952 sn-74700 1957 sn-84800
1910 sn-28400 1945 sn-63300 1953 sn-78600 1958 sn-92500
1930 sn-45700 1951 sn-68800 1955 sn-81600 1960 sn-102000
1960 sn-364200 1966 sn-397700 1972 sn-420500 1978 sn-440000
1961 sn-370700 1967 sn-401500 1973 sn-424900 1979 sn-444000
1962 sn-376900 1968 sn-405200 1974 sn-430300 1980 sn-446900
1963 sn-383100 1969 sn-407500 1975 sn-433400 1981 sn-449700