I have wondered about that myself. It is listed as polished steel. It is interesting tho. It could be that Pietta is copying the way muskets were finnished in the Civil War. They were finnished in what the armories at the time called "in the bright". The bbls on most all U S muskets, (not British Enfields) was highly polished, to almost chrome looking. Other than that I don't know. I am tempted.
Rebel Dave