I have four 1858 Remington, 2 are stainless target models. One a Pietta and the other a Uberti. I found the stainless target Pietta, the brand Cabela sells, to have .457 chambers. HOWEVER, the standard model 1858 Remington Pietta has .454 chambers.
So go figgure. They are well made, good lock-up and, based on the limited number of times I have shot them, they shoot quite well.
For the low cost, you can't go wrong.