You are allowed to post unboxing videos of unreleased product only if the entire card set has been officially previewed by Wizards of the Coast or an approved 3rd party. You can confirm this by checking the card image gallery article of the set on the Magic website. If you are posting previewed content before the official release, be sure to clearly indicate the release date wherever this content is posted.
If you receive product or cards from a set before it has been fully previewed, you may have received that product in error. If this happens, please do not share or advertise product content that has not been previewed and reach out to WPN Retail Support for further guidance.