Yes, the whitelisting will be closed once the list is full. You can apply here to qualify for the beta test and once all the slots are filled, the whitelisting will be closed. It is unclear whether there is an exact deadline for this, however it is suggested that you apply as soon as possible to secure your spot. Additionally, it is unknown if the game is a p2e, so it is best to check the official website or contact the developer for more information.