Yes in 1860 Stevens made a double barrel, all steel barrel and its has external hammers.
I can't answer your question but I have a series 5 16 gauge. your post is the first time I've seen reference to this gun on the internet. M
about 100-150 dollars..more or less
yes it is.
J. Stevens Arms Company
This gun was made from 1912-32 and it is valued from $50-300 according to its shape
Sn data is located in some books published on the Stevens company.
go to eBay lol