The only hope for the 748 is an uptick in demand for large freighters, which seems unlikely.
Yes some 747-8F orders would help to keep production going beyond 2016 but there are currently only 8 unfilled orders. There's an expectation that ABC will take more but Boeing may still have to stop 747 production in 2017.
The orderbook/unfilled orders for the 747-8 ( the passenger version ) is looking very thin with only 6 of the 13 remaining looking likely to be delivered ;
6 for Korean will happen
4 for Transaero will not be delivered ( 2 built and stored )
2 for Arik unlikely to be built
1 BBJ built but in long term storage
Orders needed urgently.
Korean No. 5 already been rolled out, No.6 & 7 are in final assembly line, only 3 (No.8-10) new passenger frames waiting to be made.
The cargo order is equally bad. Korean Air Cargo's No.7/final frame is already in FAL. The final frames for Cathay and Cargolux (both their No. 14) are waiting to get into FAL in the next couple of month, SilK Way's final two frames No.4 is already in FAL, No.5 is waiting to get into FAL very soon.
The only remaining order not showing in FAL or waiting to get into FAL, is the remaining 6 for Nippon Cargo - we know they are not urgent to take them.
Even if AirBridgeCargo taking 3-4 frames each year, with the current production rate, Boeing would be OK for 2016, but 2017 would be a different story, if they can't get new orders or getting very small orders. They have to carry on until they finish those two AFO aircraft, looks like it maybe just about before they shut the production line.