400NL reckless bet river?

[Vinetou]

PokerStars No-Limit Hold'em, $4 BB (2 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Hero ($415.50)
BB ($933)

Preflop: Hero is Button with Q[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/diamond.gif[/img].
<font color="#CC3333">Hero raises to $12</font>, BB calls $8.

Flop: ($24) J[img]/images/graemlins/diamond.gif[/img], 3[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $20</font>, BB calls $20.

Turn: ($64) 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $32</font>, <font color="#CC3333">Hero raises to $108</font>, BB calls $76.

River: ($280) 6[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $275.5 (All-In)</font>, BB calls $275.50.

Final Pot: $831

Is this a reckless bet on the river? What do you think is a calling range of a solid villain here?