Originally Posted by deplaylady

Okay, there is something I am confused about with my 401A. According to this site: http://www.ismacs.net/singer_sewing_...s-400-499.html
the 401A started production in 1957, but according to this site:
http://www.singerco.com/support/mach.../double-letter
and the serial number on my machine being #NA703991, the machine's number was assigned in 1951. So - which is correct?

Unless - maybe the first site got its dates from the manuals it found and only found ones from later dates?