Hello Maurice
there are no seams on the outside of the bottom, nor traces of gilding inside .
The inside has a coating that over time it became dark , but do not know what is.
About the corrosion, I posted a request for information on a forum of tobacco sniffers (yes, also this is on the Internet ) . They deny that tobacco can corrode, and one of the contributor says
"Just think of the original boxes in which the tobacco is sold, I keep some for several years and the boxes, also made of metal, are not at all corroded"
It was the type of hinge , so discordant with respect to a base metal box, tin welded, that put me in doubt .
The lid is hollow , and there is a chink where you can insert a piece of paper .

With this system, I tried to clean up the inside of the lid and came out a few small grain that seems sand , but not snuff.
You've convinced me that it is a snuff-box, but a small doubt I have left.
Regards
Amena