The best thing I have ever seen was a brochere from the manufacturer.
In the 3 ring binder where you keep your log book; (you do have a binder don't you) a page of original vehicle pictures would be very helpful in a protest. Pictures of other "stock" or as manufactured vehicles will enhance your position. Manufacturers parts pages from dealers help with additional devices and parts #'s which may be factory but not on the normal car sold to the average driver. Parts counters guys will copy this stuff if you ask.
Older brocheres can be found a swap meets, e-bay, collector clubs, etc:
Good Luck