Phail:
Depending upon how large the "pinhole" is, there are only three potential repairs. The first is a Teague liner. If Teague would even consider such a job. The other is to have the barrels sleeved or replaced.

To my knowledge, no other options are available. And in their present condition, the pinhole barrels are not shootable. Thus, the gun is only slightly better than a "one-barrel set."

Best, Kensal