During Hal's "Restrain yourself" talk to Dewey Hal has a domino in his left hand and near his face. Change camera and his left hand is near the floor and his right hand (sans domino) is near his face. Then his left hand is near his face.
Just before the end when Hal accidentally pushes over the dominoes, you can see a big flag of the USA all over the table falling over. It then switches to a shot where a hand with a helper tool, pushes over only the very end of the flag which is now clearly only at the end of the table. The hand now rests behind it on the empty table. The toys at the end also moved closer together. This was very clearly a do-over of only the last part.
At the end when all of the dominos are falling, when it gets to the American flag falling, a crew members hand can be seen pushing the dominos.