Is this rivet thing supposed to be attached to the iron mess? cleaned up some

[Bramblefind]

Any ideas about what is going on with this piece? Is that a decorated rivet?

Found it in the foundation of a farm outbuilding. I think the building was used for apple/cider/canning storage.

Thanks!

 

[Bigcypresshunter]

I think the copper button/rivet thing is a snap. I think something was snapped on and disintegrated away.