If very possible. LSU travels well and it isn't that far of a trip. Plus, there are probably a lot of LSU alumni in the DFW metroplex. LSU allows Texas residents to attend at in state tuition and they have a large number of Texas residents attend LSU. Also, tickets are open to the public so far more available to the visiting team as compared to the regulate season.
They may not show up at all but this is a large state school with good travel history (fans that is) and probably a large alumni base in the area so the potential is there for a strong LSU turnout.
Plus, SMU was a ranked team with a lot of national pub so it would be a huge win for LSU on the road.