The F-450 / 550 Chassis-cabs are unchanged when it comes to the load capacity, tires/wheels, etc. The F-450 pickups are the ones that changed.
On another note, I wouldn't be surprised to see Ford phase out the F-350 DRW and make the F-350 an SRW only truck since they've done this to the F-450 pickup. Now the only real advantage the 450 has over the 350 DRW is towing capacity so why keep both? The payload is virtually the same.
RIP Steve (Bricks) Price........Godspeed my good friend. RIP Paul / Hdslider.....you are truly missed.