Looking at the drop down list in MP for external pressure sensors ( BARO_PROBE_EXT) there is an array of different barometers to choose from in ArduRover 4.5.3 and up.
From the baro library it appears that not all of them are currently supported in Rover ardupilot/libraries/AP_Baro at master · ArduPilot/ardupilot · GitHub
Am I getting something wrong?