My late brother had a 16ga. pump shot gun. His son, my nephew has it now. The markings on it is, Stevens Browning, model 620, the numbers on it is 087103. From what I ,under stand, Firearms made after 1968, must have a serial no. So, this must be the mfg. no. What we were wondering was, is there any way to find out when this was made, by useing this no. If we can, how do you go about finding out how to do this. Thank you for your help.