It is too soon to say for sure. The 747-800 has not been formally launched so no airline will publicly commit to it until such time as it is guaranteed to proceed.
The odds are good it will be offered. The A380 is too big for some routes and the airline interest in the 747 upgrade has been great.
The 747-8 has been formally offered; there are currently a few dozen orders for the freighter version (from one of the Japanese airlines and Cargolux) and orders for the passenger version are expected this year.