Hi Cent, I went to the CHP (City Highway Patrol) and asked the officer in charge. A Colleague of mine hired an even heavier truck with friends and they even had an accident, but the license was never an issue.
At my insurance (AAA) I was honest too, but the didn´t care ether.
At RV-Rentals they are also very relaxed with the drivers licenses. Some ask for the international driver license but in fact it is not needed for thr US (at least for germans).
So don´t worry about the weight restriction too much...
Have fun
Ben