I saw no indication of a MWAA 700 MHz site at either DCA or IAD today. Looked at the entire Public Safety band from 769-775. The only decodable control channels near DCA were from the PG system; and the only decodable cch at IAD were from Maryland FIRST. I didn't check the Dulles Access Road, but I suspect there weren't any along that route either.
The new 800 P25 MWAA was strong at DCA, along the Dulles Access Road, and at IAD. I wasn't logging TGs per se, but the ones I heard sounded like facilities and services - no public safety yet. The system IDs as WPAY962, although there is no FCC record for that callsign. WPAY961 is the callsign for the legacy 800 system.
I'll be submitting frequency updates to the RRDB.