I'd grind across the whole face area first until the weld is close to flush with the with the face of center of the balancer and crank snout.
If it is weld it will likely then break or crack, use a slide hammer to try to pull it.
If the goofs that did that would have just used a small amount of retaining compound on the ID of the balancer hole in the last 1/8 inch left as it was being installed they wouldn't have caused the mess.
I don't understand why they wanted to make installing those dampers so difficult in those days, as well as hoping they would not come off not being retained with a bolt.
I would like to see the factory install process.
