Model numbers are usually coded with the year of introduction to the market.

Serial numbers are coded with the date of manufacture, typically either year & month or year & week.

Each manufacturer uses a different coding syntax. Some are fairly easy to figure out, others require a decoding chart.

Some manufacturer coding methods are outlined here: How old is my appliance?

Thanks for the info Dadoes.

Duh...I should have googled. I was hoping that maybe the first number in the serial number would be the clue. But it looks like I need to take a chart to figure out the letters.