What is the age of a 12 gauge Charles Daly double barrel serial 106399 made by JP Sauer and Son in Prussia with fluid steel krupp essen on the barrel?

I received a letter from SIGARMS dated May 13, 1997 stating "All Sauer production records were lost in 1945 when the Soviet Army occupied the Sauer factory. For this reason, we are not able to offer any information on your shotfgun..... recommend you have a qualified appraiser examine your shotgun.....or contact the National Rifle Association for a recommendation." I have SN 186309. I received a letter from SIGARMS dated May 13, 1997 stating "All Sauer production records were lost in 1945 when the Soviet Army occupied the Sauer factory. For this reason, we are not able to offer any information on your shotfgun..... recommend you have a qualified appraiser examine your shotgun.....or contact the National Rifle Association for a recommendation." I have SN 186309. I received a letter from SIGARMS dated May 13, 1997 stating "All Sauer production records were lost in 1945 when the Soviet Army occupied the Sauer factory. For this reason, we are not able to offer any information on your shotfgun..... recommend you have a qualified appraiser examine your shotgun.....or contact the National Rifle Association for a recommendation." I have SN 186309.