The word from Cole's:

New barrels - (laughter) $10k and 1yr+ wait

Old Barrels - even if you can find them, generally not wise to fit anything other than new barrels on the gun. The barrels were hand-fitted to their original action, so there is no guarantee that they can be safely fit onto another action. Even if the fit looks okay, it still may not be safe.

Take-away: don't buy an older S2/S3 if you can't live with the barrel configuration.

Such a long, long time to be gone, and a short time to be there.