Which of the following is NOT a requirement for the 5th wheel during inspection?

The requirement that the 5th wheel must be rusty to indicate wear is incorrect because rust is a sign of corrosion and deterioration, which can compromise the integrity and functionality of the 5th wheel. During an inspection, the goal is to ensure that all components, including the 5th wheel, are in good condition and free from damage. An inspection should focus on ensuring the 5th wheel is properly maintained—meaning it should be well greased for lubrication, the pivot pin must be secured to ensure stability, and the platform should be free of broken parts to function safely and effectively. Rust is unacceptable in this context, as it indicates that the component may be weakened or could fail. Therefore, having rust would be a clear indicator of a potential problem, not a requirement.