Not exactly. The headset only serves as an extension of the antenna. There still needs to be a receiver in the phone that will interpret the signals. The headset is just a piece of wire. It can't replace an antenna.
Sorry I should have been more accurate. The phone has to have a FM chip to receive an FM signal. If you fire up the FM app you get the message to plug in the earphone in order to receive an FM signal. My phone doesn't have a radio chip and I get a message telling me so.