EA has now confirmed some of the goodies you can get if you decide to pre-order the shooter.
If you pre-order the game through Gamestop or Amazon, you will get the Premium Expansion Pack and a pair of real dog tags with a code for in-game goodies.
And if you pre-order it through Origin for PC you will receive the
Premium Expansion Pack along with Battlefield 4 beta access and
‘bonus in-game content’.