Remington 700 Custom .243 Douglas barrel

Question
What is the age of the gun?
ser. # 212975
The barrel does not have any date codes stamped on it.  "G. R,. Douglas, .243, {and a circled} XX" are the only markings on the left side of the barrel with no marking anywhere else on the barrel.

Answer
Its a high end after market replacement barrel.
The date code would be on original barrel.
You can contacting Douglas.
http://www.douglasbarrels.net/

There is no way to date by serial available to the public.
You can try asking Remington.
http://www.remington.com/pages/our-company/our-company/company-info.aspx