Remember that it is always easier to prove that something is true than it is to prove its not true. Proving something is not true means you've been able to capture and review ALL the evidence. In today's world of old trucks that is a very difficult thing to pull off.
This is why there are people who live to determine provenance of antique stuff. Its hard to do with confidence and when some antiques are worth big money the advantages of being there can be very rewarding!
