450s and 550s aren’t “one tons”. And if you really wanna know, the earlier Ford F450s had Dana 80 rear and Dana 60 front axles, the same as Dodge 2500 with manual transmissions came with.
Most 3/4 ton and one ton trucks use the same wheel bearings.
The engines and transmissions are the same.
Rather than vague terms like duallys are heavier duty this or that, try calling out specifically what is different. Generally, it’s a couple-inch wider rear axle to clear the inside tires against the pickup bed, and not even that if it’s a cab & chassis, usually an extra leaf or two, and often duallies don’t even have a factory sway bar. Those are actually more common on SRW trucks. The brakes are usually the same part number.
I’ll only haul my camper on a dually. I own three of them. The extra tire capacity and stability that comes from the width is game-changing. But ALL the drivetrain and chassis parts are the same except those few things to make it mount the extra wheels.
That’s how they’re built.