Well I would start with the suspension.
I actually like the ball and cup design. I have one in the basement "art" with the linkage still attached to a I beam.
If you come across an orgional A your going to find wood somewhere in the coach. It was lightweight yet "strong". How much you find depends on what you have. There were several diffrent coach builders that the unfinished cars went to.
The interior material may lend itself to a few hints.
The glass, batteries, fuel tank, carburatior, even door strikers may provid hints to what you actually have.
At this point a few pictures 1/4(hood/fender), 3/4(trunk/rear door), front, engine bay, interior dash, seats, suspension, headliner, etc would answer several things.