Mark,
A178A8 decodes to N194SS, not assigned by FAA, no previous with the registration that I can find
A5176B decodes to N427UJ , not assigned by FAA, no previous with the registration that I can find
A769EB decodes to N577RK, not assigned by FAA, no previous with the registration that I can find
AD2000 decodes to N945CU N950F, FA50 allocated AD3524, also used AD1524 in past.
Regards
Alan