Most e450 and even e350 tires from that manufacturer time range are overloaded.
I found this out firsthand a few months ago when traveling back from the beach in June. One thing the recovery truck driver mentioned to me was this fact. He's seen too many class C RV's over the years that had issues with tires because the larger class C's are already at the max weight when coming from the manufacturer. Add in all of the "stuff" we carry onboard and we are asking for blowouts or failures, especially on the "steer wheels".
He recommended a manufacturer that makes a direct bolt on wheel replacement to upgrade the factory wheels from LTV tires to actual Truck tires (17.5 inch) and having a much large capacity of load carrying... Rickson Wheels in Maryland makes a bolt on wheel that takes a truck tire of 17.5 inches and gives a much larger capacity for the tire, thus causing less chance of a failure that will surely leave you stranded on the roadside.
I purchased 2 rims for the front for under $500 for the pair and had tires installed locally and no more issues with tire problems when I travel.
Upgrade your class C to truck tires and avoid all the issues with factory tire sizes and makes and you will travel with a lot more confidence.
Nothing better than piece of mind that you have wheels/tires that can actually handle the loads. The manufacturers would have you think otherwise but you NEED to upgrade the wheels to truck tires.
https://ricksontruckwheels.com/wheels-ford-e350450.php