Four rubber half inch long, three mm caps/sleeves behind grill

My son accidentally dropped the SoundDock portable and the grill popped off. I noticed four small rubber caps that are approx half inch long, 3 millimeters wide, and 2-3 millimeters thick. They form a block shape on the outside and the inner slot covers something that appears to be a millimeter thick. I've never disassembled the unit before so I have no idea where they go. The rubber cushions (lower left/right) and velcro pieces are present.