Dear PTCGO staff,
This trainer kit "Sun & Moon Trainer Kit: Alolan Sandslash & Alolan Ninetales is automatically opened even after the first one is opened. Therefore, it is impossible to own a sealed version of this. I also do not think the sealed version is coded in the game as I do not see it in the collection tab under packs.
Please let me know if you need anymore details from me and I am using the most recent version of the client.