I think you have a right to be skeptical. Unfortunately, when there is money funneling into precious objects, be it PMs like gold and silver, or even just antique items there will always be counterfeiting of those very objects.

We see it everywhere... it's unfortunate, but being skeptical and educating yourself on them will guide you toward the real thing and away from the junk.

I'm no expert, but based on what you've shown and explained (never mind your expertise) I'd tend to agree that they're fakes.