Nah, double battles are bring 6 pick 4
I am aware of VGC rules, I believe it was stated on the PGL that this is different and brings three.
Directly from the PGL:
Competition Rules
• This competition uses Double Battle format.
• Players may use only Pokémon from the Alolan Pokédex. Only the Alola Form of Pokémon with regional variants can be used.
• Zygarde, Cosmog, Cosmoem, Solgaleo, Lunala, Necrozma, and Magearna cannot be used.
• Mega Stones are not allowed.
• Items are allowed, but Trainers may not have duplicate items in their Battle Team.
• Register three to six of your Lv. 1–100 Pokémon to your Battle Team.
• All Pokémon in this competition will automatically become Lv. 50 for the duration of each match.
• Three of the Pokémon you register to your Battle Team will be chosen to battle in each match.
• A 10-minute time limit for each player will automatically be enforced in-game, beginning at the start of each battle. When a player’s time limit expires, that player will lose the game.
• At the beginning of each battle, players have 90 seconds to select three Pokémon with which to battle.
• At the beginning of each turn, players have 60 seconds to select a move or change the Pokémon in battle. If a player has not made his or her selections at the end of this period, the game will automatically make selections for the player.
• Players may battle up to 15 games per day of the competition. Any unplayed games will carry over to the following day. A new day begins at 00:00 UTC.
• For additional details, please come back to check the competition’s regulations page when registration opens.
