How old is my 20 gauge Remington model 17 pump shotgun serial 68463?

what is the value of a Remington model 17 serial number 43748 20 gauge.The Remington model 17 shotgun was made from 1917-1933.There were approximately 48,000 made during this time frame.To accurately date your shotgun,there should be a 2 or 3 letter code on the barrel.Please post these letters do date your shotgun correctly.