My father gave me a shot gun that his father had. It is a Stevens 16 ga. Patented August 12, 1913. Under the fore grip is the number 365. and what looks like IL. I would like to know how do I find out it's age. What size 16 ga shells does it take and where can I get a front sight for it. I have looked up stevens on the internet but have not figured out how to find it. Thanks for any info Lee