Both barrels are smooth and bright with no visible traces of rifling. I have not had the thickness measured myself, but I did while googling around find a listing for this exact gun (same serial number) sold at auction in 2016. (And for a heck of a lot more than I paid for it). That listing says the bottom wall thickness is .04. In any case, I will have a local gunsmith take a look before I fire it.

https://auctions.morphyauctions.com/lot-428104.aspx