Serial number range: 1231001-2499150 (1954-1971, approx. 9,200 produced). Production by year: 1954: #1231001-1231100 (100 units); 1955: #1325001-1325500 (500 units); 1956: #1363001-1413500 (2,000 units); 1957: #1477101-1537500 (2,000 units); 1958: #1557001-1558000 (1,000 units); 1959: #1677001-1680000 (3,000 units); 1961: #1875001-1875500 (500 units); 1968: #2279751-2279800 (50 units); 1971: #2499101-2499150 (50 units).