This should be asked in the Black powder section. There will be more members there that can answer questions concerning cap and ball replicas.
I have a number of black powder guns Umberti, Flli Pietta, Dixie and Navy arms. All were made in Italy.
The only one I have somewhat like yours is an 1860 Dixie gun works which is in 36 Cal and octagon barrel, with the naval seen on the cylinder.
It’s not unusual for Italian manufactures to not mark their guns. I think that they are built and sold to companies like Dixie and they stamp the gun. I have an 1851 Navy and the Dixie lettering across the top of the barrel are nothing like the manufacturing markings throughout the gun. Of the 9 that I own only 5 have manufactures name on them the remainder ether have no name or have the US company that sold them
I’m afraid that none of my guns match the markings on yours but then again I only have two 61’s.