After reading all the comments and Q&A about the car, I see these references to the markers:
"I (the seller) asked him (the owner) where his Dad purchased the car in Europe and the seller said that he is not exactly sure. However, if he had to bet, he’d guess Brussels. His father had a few offices in Europe at the time. (and a later clarification by the seller): I was notified that the rear brake light was added after the vehicle came to the United States."
By the way, the vehicle sold this afternoon for $81,500.