It's definitely possible that they're storing the passwords using reversible encryption. However:

1) In my experience, it's often harder to set your app up to use reversible encryption instead of hashes, especially if you're using an existing authentication library. In a case like this, I would assume the path of least resistance is more likely.

2) Storing passwords as reversible encryption is almost as bad, as the person who compromises your security would likely have access to your application code (and therefore the key to decrypt the passwords), and the negligible benefits of being able to retrieve passwords are not usually worth the potential liability.