The date of manufacture is determined by the SERIAL NUMBER on the appliance. The following link explains how to determine the age of your Whirlpool appliance:
The SECOND DIGIT in the serial number represents the YEAR the appliance was manufactured. The first two numbers following that digit, represent the WEEK (52 weeks in a year) the appliance was manufactured. So, based on the serial number you have listed, the WASHER was manufactured in October of 2005.
These appliances are commonly sold as a set, so you may find the dryer was manufactured around the same time. If you need assistance determing the age of the dryer, please post back with the SERIAL NUMBER and let me know. I hope this helps you.