A gladiator who won several fights, or served an indefinate period of time was allowed to retire, in many cases to continue as a gladiator trainer. Those who did win or buy their freedom, or at times at the request of the crowd or Emperor, were given a wooden sword (rudis) as a memento.
Yes, in ancient Rome, gladiators could be awarded their freedom after winning a certain number of fights or through other means, such as good behavior or being granted freedom by their owner.