Most Navy Arms 1860 .44 were made by Uberti. Near the end of Navy Arms revolver retailing they were made by Pietta.
You should be able to locate an octagon with a " U " inside it if an older Uberti. If a newer Uberti it will have Uberti on the barrel, likely the barrel's bottom.
Pietta/Navy Arms will likely be marked on the barrel. Might just have *** in a diamond.
Around here second hand, like new Uberti 1860's bring on average around $200 - $250. A bit less for Pietta's.