Straight from the Euroarms webpage:
Specification:Naval Rifle pattern 1858 two band.
Calibre: .577"
Barrel Length: 33"
Overall Length: 48 1/2"
Weight: 8lb 8 oz (approx).
Stock: Seasoned Walnut with solid brass furniture.
Barrel: 5 grooves of progressive depth (.008" deeper at breech than muzzle) 1 in 48" twist, cold forget.
Sights: rear sight graduated to 1100 yards, front sight fixed.

At least they are showing the progressive depth rifling and 5 groove barrel, which I think was used after 1860.
I'm looking for something to soI can retire my original mint 1860 dated L.A. Co. 3 band.
I know the L.A. Co. were not as widely used during the war, but it would be easier to duplicate than the normal "Tower" marked Enfields. All the original L.A. Co. that I have seen has the small (not triangluar) lower sling swivel, round eared lock screw washers, and VR under the crown.
Well, off to work. Thanks for the info.
Virgil