Each time you mention CA on the forum, that will bring lot of OT whining.
Coming to original question, I was using F450 commercially in the past and even the registration laws are like 100 years old, they were not enforced, meaning lot of heavy truck were registered at their empty weight, not the gross.
The side weight stickers and declarations come to play +- 10 years ago, so now you don't register truck under its listed weight, but under what you think you might weight total at max load during the year.
You will see some commercial 350/3500 trucks with 45,000 lb stickers as that is what they haul.
If your truck is used for camper and commuting only, you can go to DMV with camper on for inspection and have it registered as non-commercial (they have special term for that that I can never remember)
Doing that on my F350 saved me over $400 on annual weight fee, but don't get cough with cargo on your truck.
Pickups in CA are trucks with GVW below 13,XXX lb. Weird number that I could never remember.