Information is easy once you consider that Montgomery bought in all major components. You get info on all the seperate bits of the jigsaw puzzle. Your bike has a J.A.P. engine, Albion gearbox, Lucas electrics, Amal carburettor, etc on all of which info is plentiful. I would also bet it has British Hub Co wheels. About the only parts uniquely Montgomery are the frame and possibly the forks.
Both BMS and the VMCC Library have a selection of owners leaflets and catalogues from various years, you shouldn't have any real bother getting appropriate pictures. Supposedly Montgomery only used two types of frames throughout the thirties regardless of the engine size and regardless of the year.
Finally, you have one huge advantage. You will never have problems with rivet counters. You know, the person who looks at your restored bike and tells you its wrong because that model should have a chrome plated sump plug or some such nonsense. Who will ever know what is right?
You certainly have the basis of a sweet bike.
Cheers,
