I would suggest you do some research in the Hermes threads, or use your search engine of choice.
As a general rule, these types of questions fall under the authentication thread. However since the sale is completed, (ie you bought and received the item) you would need to seek the services of a third party authentication service for any questions about authenticity.
It’s a TPF policy not to discuss what makes things real vs fake. It’s a way to try and limit the unscrupulous folks who might use the information to produce a better counterfeit