u/One_that_never_was

These lists were made with an XRF (if I'm not mistaking) , purity seems to jump a percent around the rivet in the back, yet on the bottom there's a yellow tint almost like the gilding in front, however it didn't detect any gold around the rivet, gilding on front is shown to make up 11.79% of the scanned area, it is very thin, could the silvery part of the back rivet just be a very thick silver plating on a copper rivet and a few atoms are leeching out? Or is it solid silver like the rest of the medal with a weird patina around the rivet base?

Napoleon III appears with a beard most of the time but I've seen some coins from the 1850's that have a similar portrait but it still looks very similar to Napoleon the 1st

They look pretty good and are 10$ each which is pretty low for them, however the seller is located in Poiana, Romania, at three km away from the black sea shore, should I be concerned about the risk of bronze disease or any corrosion? The seller says they've been kept in boxes inside boxes but still, should I avoid them? Could I keep them next to other bronze stuff? Maybe even attempt to rinse them?