You'll find 2 letters on the left side of the barrel up close to where it meets the receiver and just above the forearm. This will be your date (month and year) of manufacturing, that is if the barrel is original to the rest of the gun. If the barrel is original to the gun you'll find the same number as is on the right side of the receiver on the bottom side of the barrel by the gas cylinder
Below is link to the chart with the code for dating. Hope this helps you out.
http://www.rc-trucks.org/remington-f...al-numbers.htm
Here is another source that you can check with.
http://www.remingtonsociety.com/foru...php?f=7&t=4463