The barrels sure do not appear to be Damascus to me. I have no idea why the records would refer to Siemans-Martin Chain Steel, unless perhaps it was known that the grade of steel used is one primarily intended for roller or lifting chains.
The speckles on the barrel are a mystery too. It almost looks like it was sprayed with acid, and then was wiped off quickly enough to not pit the barrels, but remained on the surface long enough to remove the blue. I cannot tell it the barrels have been hot blued either, but would not rule that out. At least it doesn't look like the stamps have been obliterated by a buffing wheel. I hope we get an update with more details after Dan Morgan examines them.
