Anyone raise this river?

[bnorthro]

SB is the important player in this hand, his stats are like 59/0/0.3 over about 35 hands. He hardly ever leads out when first to act, and he calls down and chases A LOT. He'll call with losing hands a lot too.

His flop lead looked a lot like a 3, just because it was unusual for him to take the initiative. I planned on folding to a 3 bet on the turn, or if the turn wasn't a 10, K, or [img]/images/graemlins/heart.gif[/img].

Sorry for the format, Eurobet, $2/4 5max

Hero is in BB with 10 [img]/images/graemlins/heart.gif[/img]K [img]/images/graemlins/heart.gif[/img]

Preflop
<font color="blue">1 fold, UTG+1 calls, 1 fold, SB completes, Hero checks.</font>

Flop 3 sb
3[img]/images/graemlins/spade.gif[/img]3 [img]/images/graemlins/heart.gif[/img]2 [img]/images/graemlins/spade.gif[/img]
<font color="blue">SB bets, Hero calls, UTG+1 folds</font>

Turn 3bb
3[img]/images/graemlins/spade.gif[/img]3 [img]/images/graemlins/heart.gif[/img]2 [img]/images/graemlins/spade.gif[/img] K [img]/images/graemlins/club.gif[/img]
<font color="blue">SB bets, Hero Raises, SB calls</font>

River 7bb
3[img]/images/graemlins/spade.gif[/img]3 [img]/images/graemlins/heart.gif[/img]2 [img]/images/graemlins/spade.gif[/img] K [img]/images/graemlins/club.gif[/img] 6 [img]/images/graemlins/heart.gif[/img]
<font color="blue"> SB bets, Hero calls</font>

I don't thinik the 6 helped him because he check/called all his draws before this. I was just puzzled by him leading every street.