1/2 stud high heads up

[kgrad5]

ok, this is my 5th hand at this table. villain has played every hand so far and has called with absolutely nothing the whole way to spike a miracle card on the river.

im dealt [ 8 [img]/images/graemlins/spade.gif[/img] A [img]/images/graemlins/club.gif[/img] 8 [img]/images/graemlins/heart.gif[/img] ], i dont remember the cards everyone had but i do remember my 8s were live and 1 A was out. villain limps with the 2 [img]/images/graemlins/diamond.gif[/img] first person folds i complete and its folded to villain who calls.
i catch the A [img]/images/graemlins/diamond.gif[/img] and the villain pairs his door with the 2 [img]/images/graemlins/spade.gif[/img] and thinks for a second then checks, i think and double bet 2$ because i know he will call.. is this standard?