River fold too weak-tight?

[tree_stump]

I really have no reads on the villain here...

Party Poker No-Limit Hold'em, $ Hero (9 handed) converter

MP2 ($78.45)
MP3 ($30.05)
CO ($18.75)
Button ($40.55)
SB ($24.5)
Hero ($34.85)
UTG ($22.9)
UTG+1 ($23.5)
MP1 ($3)

Preflop: Hero is BB with K[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/club.gif[/img]. SB posts a blind of $0.25.
<font color="666666">6 folds</font>, Button calls $0.50, <font color="666666">1 fold</font>, <font color="CC3333">Hero raises to $1.5</font>, Button calls $1.50.

Flop: ($4.25) 5[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/heart.gif[/img], 2[img]/images/graemlins/diamond.gif[/img] <font color="blue">(2 players)</font>
<font color="CC3333">Hero bets $4</font>, Button calls $4.

Turn: ($12.25) 3[img]/images/graemlins/heart.gif[/img] <font color="blue">(2 players)</font>
Hero checks, Button checks.

River: ($12.25) 9[img]/images/graemlins/club.gif[/img] <font color="blue">(2 players)</font>
Hero checks, <font color="CC3333">Button bets $3</font>, Hero folds.

Final Pot: $15.25
<font color="green">Main Pot: $12.25, won by Button.</font>
<font color="green">Pot 2: $3, returned to Button.</font>

Checking the turn and folding the river too weak-tight after showing so much aggression, or am I right to assume he's got an A or Q at this point?