8's on the bubble

[BigDave]

I am curious how you guys look at a medium pair on the bubble. In this situation, I consider that my opponent is attempting to steal from me in the big blind:

NL Hold'em $20 Buy-in + $2 Entry Fee Level:7 Blinds(200/400) - Monday, January 10, 00:42:44 EDT 2005
Seat 3 is the button
Total number of players : 4
Seat 3: wobblo ( $3415 )
Seat 5: Frohgg ( $1710 )
Seat 7: hero ( $1640 )
Seat 9: supadphat ( $1235 )
Trny:8553940 Level:7
Blinds(200/400)
** Dealing down cards **
Dealt to hero [ 8s 8c ]
supadphat folds.
wobblo folds.
Frohgg raises [600].
hero is all-In [1240]
Frohgg calls [840].
** Dealing Flop ** [ 9d, Ad, 5c ]
** Dealing Turn ** [ Th ]
** Dealing River ** [ 7h ]

If you "know" that SB has two cards over your midpair, do you still play this the same way? Is it to late to call and look at the flop before all-in?