Fallout 76 beta will show endgame content
The progress that players make in the test will be carried over to the full version.
Bethesda has updated the Fallout 76 Beta FAQ page with information of interest. As indicated therein, players will have Access to all of the content of Fallout 76 during the testing phase, and you will be able to maintain your progress once the final game goes on sale in November.
Taking into account the multiplayer nature of this installment, we assume that this progress includes both level and weapons, equipment and mission progress. Little else is known about the beta, except that it will be available sometime in October and that the invitations will arrive little by little. To participate, you need to reserve the game.
Fallout 76 will be released on PC, PS4, and Xbox One on November 14. It will invite us to explore a new haven and a huge open area in West Virginia where players can cooperate or fight each other.