12 years of B&W ownership I have never covered my hitches. I make sure to clean and lubricate the jaw surfaces where they contact the kingpin and side to side pivot zerk and where the head mounts to the supporting arms. Sure it does not look like this any longer from sun exposure. Next truck will receive a new B&W.
My Dad used to cover his with a garbage bag.
2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"
"HeavyWeight" B&W RVK3600
2016 MobileSuites 39TKSB3 highly "Elited" In the stable
2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD