From what I've been told it would be 3.5k public, with VIPs having their own event in the lounges at the Etihad,It's not open for general public or fans ... limited seating due to size of academy stadium (25% of that under current regulations), so is for City's staff and VIPs (by invitation) only.
Knowing the companies being approached for Saturday I would be amazed if this is just for City staff (most of whom have been offered tickets and flights for the game itself)