Remington New Model Army with Round Barrel

[drjldavis]

Does anyone know anything about who may have produced the Remington New Model Army with a round barrel instead of octagon?
I have picked up a Remington New Model Army with a round barrel and other modifications marked, "Belgium" on butt along with Serial #00001.  I saw a second Remington New Model with a round barrel on a gun auction. It was standard except for the round barrel.   I ran into a third with round barrel that was marked "Navy Arms" that was heavily engraved from the Uberti factory.  Are these "custom" revolvers or did someone produce them?