turned set vs fish, limped pot

villain is a pretty big fish. 46/13/2 and playing like a station. his river bet was pretty quick. this just looks like exactly 78, and seeing as its a limped pot can i give him credit for that, 23 or 73?

PokerStars No-Limit Hold'em, $6.00 BB (6 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

Hero (BB) ($716.10)
UTG ($1025.30)
MP ($526.10)
CO ($120)
Button ($739.25)
SB ($286.50)

Preflop: Hero is BB with 5http://www.flopturnriver.com/phpBB2/...es/diamond.gif, 5http://www.flopturnriver.com/phpBB2/...miles/club.gif
1 fold, MP calls $6, CO checks, 2 folds, Hero checks

Flop: ($15) 6http://www.flopturnriver.com/phpBB2/...iles/heart.gif, Ahttp://www.flopturnriver.com/phpBB2/...es/diamond.gif, 4http://www.flopturnriver.com/phpBB2/...es/diamond.gif (3 players)
Hero checks, MP checks, CO checks

Turn: ($15) 5http://www.flopturnriver.com/phpBB2/...iles/heart.gif (3 players)
Hero bets $24, MP raises to $96, 1 fold, Hero calls $72

River: ($207) 10http://www.flopturnriver.com/phpBB2/...iles/spade.gif (2 players)
Hero checks, MP bets $246, Hero...

surely this is two pair (especially 65 and 54) and the occasional whiffed draw (especially given sizing and timing tells) for us to have the required 35% to call.

should we be 3b/getting it in on the turn when we're OOP on such a wet board?

If villain is a big fish, I can't imagine not 3betting this turn vs him. As played, I'd always c/c.

sorry you cant lay this one down