Apparatus, and an associated method, for generating a message summary field. The message summary field indicates whether 802.11-formatted data packets are communicated upon a frequency range to which a mobile station operable in an IEEE 802.11 radio communication system is tuned. An indicator indicates whether an 802.11 data packet is detected. And, a reporter generates a measurement summary which includes a measurement summary field populated with a value indicating the determination. Subsequent analysis of the value of the field of the measurement summary is utilized pursuant to dynamic frequency selection operations.