The model 58 was the pre-cursor to the current model 1100 semi-auto. It was made from 1956 to 1963 and if in decent shape would be worth roughly $250 in my neck of the woods. Why don't you quit being clueless about guns and take the thing out and shoot it. You might surprise yourself and really enjoy it. And your great-uncle would be proud of you.

 

davesworld, DP is correct. Go to a range and shoot it.
I have the 58 in 12 Ga that you are speaking of. The sportsman 58 was Remington's first gas operated semi-auto shotgun. The engraving is beautiful on the reciever. Your gun most likely will need cleaning soon. Get some 2 3/4" shells in # 7.5 or #8 and hit the clay range. Keep us informed. There are several of us here who own that gun and can help you with maintenance issues. Also, please feel free to register here at SGW and become part of the family. Welcome!!