So much depends on the condition of the bolt and the hanger. I would try to remove the bolt. It is a robust bolt so there is some metal to work with. You might put a nut on the end that was cut off. Weld in the center and see if that will work like the original head. Or you could try to get it to move from the other end by backing the nut to the very end and welding it to the bolt. You will have to cut it off to finish removing the bolt. If the hanger has only minor damage then square it up as best you can. Then check the fit of the new bolt to decide if it will need to be shimmed with a washer. Unless the hanger is badly compromised I think you will be OK. It won't go all the way through and out the other side so it does have to come out the way it was put in. The nut on the far side is a lock to prevent it from getting loose.

Steve H