Can I get the flight schedules by using ORIGIN / DESTINATION / DATE of departure 2 months in advance.
And does that flight have a UID available?
The FlightXML2 function AirlineFlightSchedules can be used to query flight schedules that far in advance.
The unique faFlightID associated with flights are not generally assigned by us until a few hours (up to at most ~48 hours) prior to departure. You will need to use FlightInfoEx once the flight is closer to departure to get the actual status and its faFlightID.