1816 - Legend has it that a young Eliphalet Remington II believed he could build a better gun than he could buy, and he set out to craft such a gun on his father's forge located at Ilion Gulch, New York. In the autumn of 1816, Eliphalet entered a shooting match with his new flintlock rifle, and while he only finished second, his handmade rifle was a success. Orders for new Remington-made rifles and barrels began to accumulate from the many other contestants, and before Eliphalet left the shooting field, he was in the gun business.
Not much help otherwise. One was recently auctioned but the site no-longer connects. You might try contacting Remington for info on the builders.