You wouldn't see any certificates posted regarding the teacher's A.M. or F.A. qualifications, because these two franchises are very protective of their syllabus, and revoke the qualifications once the teacher has left the school. She may very well have tested out of the Bronze or Silver level with them, but as a former employee she is not officially allowed to advertise those credentials.
...Not that they mean much, to be perfectly honest. I've seen people pass their ISTD exams who have no business teaching. On the flip side, many of my colleagues who are well-qualified (some charging $90 and up for a 45-minute lesson, and rightfully so) have never taken an exam. In particular, the chain schools are notoriously lax on their exam standards. So while I wouldn't doubt that your teacher has taken whatever exams she claims to have, I wouldn't use them as a measure of her ability. Use your own judgement, and you'll be far better off.
Regards,
Jonathan