Does
FAA Advisory Circular 60-6B help? Paraphrasing it ...
4a) You must have the documentation in effect at the time your airplane was certified.
5c)
- A AFM is not required before March 1 1979
- A AFM is not required for types certified at less than 6000 pounds
5e) The important information from the AFM is the operating limitations, markings, placards, and maximum demonstrated engine cooling conditions. (All of which I suspect is in your Owner's Manual)
What specific information is your Instructor looking for?
Would your local Flight Standards District Office be able to mediate with your Instructor?