It took me a while to spot the graffiti on this one. I'm tempted to bid for the novelty of it. Warning... NSFW coin graffiti. Switzerland - St. Gall 1621 Silver Thaler Dav-4677 PCGS Genuine XF Details | PCGS Cert #41447830 | GreatCollections Coin Auctions Item #1091754.
Isn't the "X" shaped scratch in the circled area the "graffiti"? Looking at other examples online, I don't think it is what you might be thinking? https://d3k6u6bv48g1ck.cloudfront.n...lver-Switzerland-A60Kbzbi8lsAAAFR0VNauxlG.jpg https://auctions.stacksbowers.com/l...allen-taler-1621-ngc-vf-details-mount-removed https://en.numista.com/catalogue/pieces89659.html
If you look at the other examples in the links, do you still think it's the same thing you were thinking originally?
I looked at the image here: https://www.coinfactswiki.com/wiki/St._Gall_1623_thaler_Dav-4677. The image there is of a more worn coin but it didn't look like the bear image on the Great Collections coin. The higher grade ones you posted do indeed make it look like the bear might not have been, uh, altered.