Others here can give better advise than I but if you're on your way now before others get a chance to chime in, here's a few things..
Is it supposed to be a complete original car or a supposed 9561 car w/ parts missing/removed?.
Besides obvious Vin and Cowl tag codes, things to look for and make sure to take pics of to compare w/ other known genuine cars are the pierced hole in the cowl also make sure to get ALL Cowl tag #'s as the body #'s were sometimes consecutive also if D80 is noted check against build date..
If supposed original parts note and take pics of all engine and trans codes and stampings also check for the original BE rear axle code and if it's there get a pic or or at least pencil rubbing you can compare w/ other known genuine stampings also check fenders and tailpan for signs of emblems?.
Also try Googling the Vin as many of us here have tried to leave trails to real, fake or suspect cars on past threads here and elsewhere you may find online..
Best of luck and Happy New year!.
~ Pete