Do you have a "UL" or "CEA" label or certification for these rings?
the according to NFPA 70 the Authority having jurisdiction can refuse to allow them to be used?
the "AHJ" is the ultimate final say on whether your ring in the jurisdiction can be used. Doesn't matter is its a great product or exceeds rating of other Hardware. if hes says no that is usually the end of it.
if he wants to fight it most inspectors of the Fire and electrical variety will except a UL rating and listing If they are not sure about it. (with CEA being the can-na-de-an equivalent)
I am afraid with out a 3rd party like UL or CEA you may not have much to stand on.
on an unofficial personal experience note. dont buck the inspector he will may you pay there and from now till you go out of business
It is better to ask him with some certifications in hand than fight him over it.