For this amulet, You can notice from the Buddhist Relics and skin texture.
From my experience, this amulet is different and obviously seen from a new made or fake.
I'm sure if you see similar amulet from other seller. You'll see the difference!
The fake relic is larger, and like glass or plastic unlike the genuine.
The skin texture or cracks of fake amulet, If you notice you'll know.
It'll new or intentionally causing a trace.