All contents of the cabin of my friend's truck, such as a few hundred dollars worth of tools, were missing. Some customs agents work out a deal with port personnel to let your truck in for less money. However, then you do not have all the forms you need to nationalize the car and to re-register in each year. One acquaintance had to pay bribes for 12 years to register his car because he had no paperwork to show how it was imported. To get your car, you need its title.
Customs agents are accustomed to seeing U.S. titles that are separate from registration.
Seeing Canadian registration, which are not separate from the title, can confuse them. In the case of my friend it was worse, because documents from the Province of Quebec regarding cars are all in French, which of course, no one in Puerto Cortes could read. Unless your Spanish is very good, do not attempt to do this procedure alone. With this he began the shuffling back and forth between the port and the customs office. Just the form to import the contents of the truck required 43 signatures.