How could one differentiate a genuine custom paper(s) from fake paper(s)?

I have heard about some instances where vehicle are impounded for not having a custom paper(s) or having fake paper(s).

Recently,a car belonging to a close friend was seized while travelling(outside Lagos) for not having custom papers by the custom.He bought the car,Honda Accord(Bull dog) not long ago.It is fully registered in Lagos on its arrival from Rep. of Benin.

Nairalander.I need more insight into the issue.