Balancer slides in on install

That's good news. Glad it worked out.

Having fixed "mistakes" in the metal shop I know just about anything can be repaired. Example they sleeve cylinders.

I could see how a rare damper such as six pack external balance damper could be repaired.

It's just metal. Bore it. Sleeve and weld into place to prevent rotation. Bore/hone to specs and keyway cut. Balance to specs. You would never know it with a good welding job.

It's a lot to do and simpler to buy another but I don't see why a damper could not be saved if push comes to shove.

Just throwing it out there.