There will be 36 dice in the Corebox. Presumably those will be the 36 dice shown in part 5 of the GenConVideo, and the Box will therfore include only 4 Challenge dice.
Now, the diary tells us that we need to roll 2 Challenge dice for a test of avarage difficulty.
Thus there are not enough Challenge dice included to give a adequate set of them to every player, even if there are only 3 of them plus GM.
We will have to pass the dice around. Really nice.
Oh, and the "Dice Accessory Pack" (9.95$) will include only 1 additional Challenge die, so we have to buy a lot of them packs to get a sufficient number of dice and to avoid dicesharing.