Welcome to the Ark DLC

Does anyone know if this dlc expanision is only available through the xbox store? I want to pre order my copy through gamestop and there site says nothing about this dlc so I want to know if this is an xbox store exclusive or if everyone gets this add on with their copy of halo wars 2

Hi, I have been talking to Microsoft over the last few days and it looks like you can only get the welcome to the Ark dlc if you buy from Xbox store