GE codes the manufacturing month and year of all its appliances into the serial number. The first letter of the serial number represents the manufacturing month, and the second letter represents the manufacturing year.
A list of all GE product serial numbers is available at GE's website, as of 2015. From GE's website, click on Support and then on the link for Frequently Asked Questions. Under Frequently Asked Questions, click on the appropriate link to determine how old the appliance is. Also available under Frequently Asked Questions is a link on where to find the model and serial number on all appliances.