I found this and called Remington, they told me from the serial # that it's a 1973.
Here's the info, I hope someone else can find it useful too.
OK, for those of you who get tired of the same old "BLACKPOWDERX" answer....Not all Remington Firearms use the "Barrel Code" for serial number location.
REMINGTON (
www.remington.com) Customer Service (1-800-243-9700 & follow the prompts) will look up your serial number and verify the age of your firearm. They are VERY helpful and courteous. It took less than a minute to look up my 1973 Model 552.