It took me a few minutes to figure out you were talking about a Singer sewing machine. You will most likely get your answer through the serial number.
Here's the website where all the serial numbers are listed:
http://www.singerco.com/support/serial_numbers.html
Here's a website site that shows you where your serial number is located on your machine:
http://www.singerco.com/support/model_number.html