Serial numbers - Brua C. Keefer
| Serial Number | Year Manufactured |
| 600 | 1910 |
| 1200 | 1911 |
| 1800 | 1912 |
| 2600 | 1913 |
| 3400 | 1914 |
| 4200 | 1915 |
| 5452 | 1916 |
| 6023 | 1917 |
| 6368 | 1918 |
| 7671 | 1919 |
| 9680 | 1920 |
| 10,271 | 1922 |
| 12,866 | 1924 |
| 13,200 | 1925 |
| 14,400 | 1926 |
| 15,600 | 1927 |
| 16,800 | 1928 |
| 18,446 | 1929 |
| 19,877 | 1930 |
| 19,900 | 1931 |
| 20,400 | 1932 |
| 20,900 | 1933 |
| 21,300 | 1934 |
| 21,700 | 1935 |
| 22,200 | 1936 |
| 22,700 | 1937 |
| 23,300 | 1938 |
| 24,008 | 1939 |
| 24,700 | 1940 |
| 25,000 | 1941 |