I have a double barrel hammer shotgun, Stub Twist, that I inherited from my grandfather and would like to know where I can find parts to refurbish it. It has a broken stock that needs to be replaced or repaired. The serial # that I can see is 146 and I found it on the barrel under the hand grip, but I am not sure if I am looking in the correct place. You see it also has a symbol the looks like an X or crossed flags and a nuber 17 on it. Also on the hand grip it has the number M20. I am so confused, as I do not know much about guns, but would like to restore this family heirloom. Can you help me.