I doubt that very seriously. The "O"s are too entitled to write out a check for a bribe and frankly, the mere fact that the applying student has "O" for a last name would be enough for the school to swoon.
If there were any bribes, they probably went FROM the institution TO the Obamas.
But being long time members of the Chicago Mob, I suspect anything of that sort was well buried through clandestine channels.