This is from the daily $200 6-max tournament. I don't recognize MP but he's an unknown who open limped so I'm assuming he's bad. The CO is a slightly losing reg who isn't aggressive enough, I think he limps behind a ton of hands here that he should be isolating with. I don't think he's the type to make a big call on the river.

Do you like this bluff? If so, would you still like it with no reads on CO?

Full Tilt No-Limit Hold'em Tournament, 80/160 Blinds (6 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

UTG (t3485)
MP (t3760)
CO (t5820)
Button (t9495)
SB (t1745)
Hero (BB) (t4875)

Hero's M: 20.31

Preflop: Hero is BB with 5, 3
1 fold, MP calls t160, CO calls t160, 2 folds, Hero checks

Flop: (t560) 6, K, 7 (3 players)
Hero checks, MP checks, CO checks

Turn: (t560) Q (3 players)
Hero bets t400, MP calls t400, CO calls t400

River: (t1760) 7 (3 players)
Hero bets t1350