I've come to find that these stock wheels are forged, but also fairly tired. Never knew the things to look for.. they were used on a truck that was heavy often, lots of brake dust, and was in the dirt/dust a lot. The cracks must have happened right after mounting the tires the last time and have had time to corrode.
They can be welded as said but it's only to buy some time. I'll need to start looking for another set. Good news is I'm only out polishing time as I've only had 300 in the wheels themselves.
When you buy used wheels and the seller does not remove the rat azz tires, it's an extra expense but also a risk with these big trucks.