Hand Reading Against an Unknown

[toss]

Party Poker 5/10 Hold'em (6 max, 5 handed) FTR converter on zerodivide.cx

Preflop: Hero is Button with 8[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/club.gif[/img].
<font color="#666666">2 folds</font>, <font color="#CC3333">Hero raises</font>, SB calls, <font color="#666666">1 fold</font>.

Flop: (5 SB) 9[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets</font>, <font color="#CC3333">Hero raises</font>, SB calls.

Turn: (4.50 BB) 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">SB raises</font>, Hero folds.

Final Pot: 7.50 BB

The fact that villain donkbetted the flop makes it more likely that he'll have two diamonds in his hand. If he had instead check-called the flop I would've call down. My thinking sound good?