Other than the likely gauge of material difference between the integrated bumper hitch and under mount weight distribution hitch, the other significant difference is going to be how each attaches to the frame. The weight distribution hitch is going to have a much larger surface area where it mounts and overlaps against the frame so that it can distribute the load and apply leverage along the frame. Hence the weight distribution terminology.
I wouldn’t bother welding that integrated hitch adaptor. That’s not going to be a distinguisher for capacity. And it’s likely internal Toyota design capacity requirements are several times higher than the stated 5k rating. So if you don’t intend to go above that rating, have at it.
I wouldn’t bother welding that integrated hitch adaptor. That’s not going to be a distinguisher for capacity. And it’s likely internal Toyota design capacity requirements are several times higher than the stated 5k rating. So if you don’t intend to go above that rating, have at it.

