When buying a used Schneider lens for your view camera, you can use the lens serial number to determine the approximate age of the lens (that is, when it was manufactured) from this table:
Serial Number Approximate Date
30,000 Dec 1919
40,000 May 1920
50,000 Jan 1922
100,000 Jan 1925
200,000 Jun 1928
300,000 Feb 1929
400,000 Apr 1931
500,000 Jun 1932
600,000 Aug 1933
700,000 Oct 1934
800,000 Sep 1935
900,000 May 1936
1,000,000 Nov 1936
1,200,000 Dec 1937
1,400,000 Nov 1938
1,600,000 Sep 1939
1,800,000 Jun 1942
2,000,000 Sep 1948
2,200,000 Jul 1949
2,400,000 Oct 1950
2,600,000 May 1951
2,800,000 Nov 1951
3,000,000 May 1952
4,000,000 Oct 1954
5,000,000 Feb 1957
6,000,000 May 1959
7,000,000 Feb 1961
8,000,000 Mar 1963
8,500,000 Feb 1964
9,000,000 Feb 1965
9,500,000 Sep 1965
10,000,000 Jan 1967
10,500,000 Oct 1967
11,000,000 Nov 1968
11,500,000 Jul 1970
12,000,000 Sep 1972
12,500,000 Mar 1974
13,000,000 Dec 1976
13,200,000 Sep 1977
13,400,000 Oct 1978
13,600,000 Oct 1979
13,800,000 Jan 1981
14,000,000 Oct 1983
14,100,000 Jan 1985
14,200,000 Aug 1986
14,300,000 Nov 1988
14,400,000 Jan 1981
14,460,000 Feb 1992
14,480,000 Jan 1993
14,500,000 Nov 1993
14,510,000 Jan 1994
14,520,000 May 1994
14,540,000 Jan 1995
14,560,000 Apr 1995
14,590,000 Jan 1996
14,600,000 Apr 1996
14,620,000 Nov 1996
14,730,000 Apr 2000
Based on information found at http://www.schneideroptics.com/large/Vintage/large%20format/serial.htm