Bet this river for value?

[einbert]

Against 90% of players I bet this river automatically (and 3-bet preflop, which I probably should have done anyway). Problem is, the PFR has a PFR of 3 after
150 hands. PFR of 3 is pretty much QQ-AA and AK right? I didn't feel like a semibluff would work unless he had exactly AK with no hearts, so I was drawing to my nut flush and (very tainted) overcards. Do I bet the river or check/call?
Party Poker 2/4 Hold'em (10 handed) converter

Preflop: Hero is SB with A[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/spade.gif[/img].
<font color="#666666">2 folds</font>, UTG+2 calls, <font color="#666666">3 folds</font>, <font color="#CC3333">CO raises</font>, <font color="#666666">1 fold</font>, Hero calls, <font color="#666666">1 fold</font>, UTG+2 calls.

Flop: (7 SB) 3[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
Hero checks, UTG+2 checks, <font color="#CC3333">CO bets</font>, Hero calls, UTG+2 folds.

Turn: (4.50 BB) 9[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">CO bets</font>, Hero calls.

River: (6.50 BB) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>

Final Pot: 6.50 BB