No MANPAD today has such capability. If the terrorists did manage to modify one to do so, they would have to attach the beacon to the outside of the plane, or affix an antenna to the outside of the plane. A beacon the size of a small piece of candy would be insufficient in size or power to get a signal past the skin of the aircraft. Beacons also need a power source, as transmitters use quite a bit of power, even small ones. So either it would need a battery pack or be wired into the aircraft's electrical system. If the terrorists can get someone that close, they won't need the flying public to carry this out.
If they have ground-to-air missiles in this country already, the chance to stop them has already passed us by. No matter how many people the TSA gropes.