Well, by itself, it isn't much of a symbol. By itself, all it symbolizes (or, more simply, represents) is how traces of the past before the Party came into power hang around: in bits and pieces that are only partially understood.

However, once you move through the song to the final line: "Here comes a chopper to chop off your head," it becomes a kind of symbolic foreshadowing. It lets us know that Winston has always been moving towards a tragic end.