Yes, they will help the ride immensely by getting the truck off the overload springs. We have a 2001 Dodge dually pulling our toyhauler very similar to your weight. Without any air in the Firestone air bags the ride is awfully harsh. I've found that about 50 psi will lift the truck and the ride smooths out and makes for a much better ride.
I also installed the Dexter EZ Flex suspension on the toyhauler and that helped the toyhauler ride smoother. Both are worth the money. IMO of course.
Howard and Peggy
"Don't Panic"