Ask your physician to show you the Box
The best way to tell this is to ask for the box beforehand. Tell the physician that you would like the box before the injections and the handout for post-injectiin care. Merely say that you want to be sure that these items are not forgotten when you leave.
Or you can be more direct and just say you would like to see the box.
Restylane, through Medicis, has a seal-like proof of purchase sticker at one end of the box. If you see this, you can be sure that it is Restylane.