According to Ned Schwing’s Standard Catalog of Firearms, the American Gun Co. was the private brand of H&D; Folsom of New York City, and the guns were indeed made by Crescent Firearms Co. of Norwich, Connecticut. The American brand was manufactured between 1892 and 1922, and an outside-hammer gun (the rabbit ears you mention) would be worth between $250 and $800, depending on condition. If it looks like it’s been used much at all, it would be worth closer to the lower figure than the upper.