They are an authorized retailer for Pandora and do specialize in retired or otherwise hard to get charms.

https://us.pandora.net/en/explore-the-brand/authorized-retailers.html

They are 20th on the list for authorized retailers, it is a by brand list.

Google is awesome, but go direct to the brands themselves to check if you're worried about something like this for authenticity (if they're not telling you they are not an authorized retailer, because at that point if it's not an 'authorized retailer' even if it's authentic, many brands will state it is not as they want you to buy direct). Usually they'll directly state if they're not an authorized retailer for the brand.

Also for Pandora;
https://us.pandora.net/en/explore-the-brand/brand-protection.html

Carol B is wrong! RUE LA LA is not owned by Neiman Marcus. It is owned by an Internet shopping company called Kynetic LCC. There is no reason to think that Rue La La would maintain the same standards as a reputable, all be it overpriced, retailer like NM. There have always been rumours and online comments regarding quality and counterfeit products associated with Rue La La. A simple "Google" fact finding check tells you everything you need to know.

I am not certain but my experience has been they stand behind the brands they sell. Frances

Oh yes! I have ordered several. Remember that The Rue is Neiman Marcus. They do not sell fakes, which I'm very familiar with.