We have followed up with Activision for further information.
We still don't know what the Black Ops III beta will consist of, but you can guarantee yourself a spot in it by preordering a physical or digital copy of the game. The beta will not be held on Xbox 360 or PlayStation 3.
The Black Ops III multiplayer beta coming first to PS4 is just one part of publisher Activision's new relationship with Sony. As part of the new agreement, all Black Ops III DLC will launch first on PlayStation platforms. Previously, DLC came to Microsoft's Xbox platforms before other systems.
In other Black Ops III news, Activision recently unveiled the game's new, 1940s noir-inspired Zombies mode, which stars actors Jeff Goldblum and Ron Perlman. The publisher also announced a $200 version of the game that comes with a working mini-fridge, but this premium edition quickly sold out. And just yesterday, Activision released a new trailer for Black Ops III's new "The Giant" Zombies map.