I wouldn't think so. Is Texas still a Top 50 team? I don't think it would be considered a bad loss.
Yes, they are top 50, and if we lose to them tonight they'll definitely be in the Big Dance, so it wouldn't be a bad loss.
I'm less confident than everyone else who says if we lose tonight we are still guaranteed a 3 seed. I think that is more dependent on what happens in the ACC tournament and the rest of the Big 12 tournament with teams like Louisville, Notre Dame, Baylor, and Oklahoma. Those four teams, if they all do well, could get 3 seeds ahead of ISU - and that isn't even factoring in Maryland, who is a lock on the 3 line right now, leaving only three other slots for teams like ISU.
Worst case scenario for ISU is a loss tonight plus Baylor over Oklahoma in the Big 12 title and Louisville over Notre Dame in the ACC title. That puts us on the 4 line IMO.