If blades were stamped with inspectors' initials, then they were made to fulfill a contract and accepted by the government. The piecemeal method of government inspection of saber components leaves open the possibility that perhaps some blades were inspected but not used to assemble complete sabers, but I don't think there could have been any large quantity of them. Saber contracts were notoriously late in delivery, and contractors were pushing everything out the door they thought might pass inspection.
I'm unaware of any contract to provide spare saber parts to the US Government post-war. There are none mentioned in the several histories of Ames. If you're aware of one, I would love to see it.
Given the glut of armaments post-Civil War and the extremely tight military budgets, I think it would be most likely that excess sabers were used to provide any required spare parts. This is supported by the fact that, of the over 203,000 light Cavalry sabers purchased during the Civil War, only 9,362 were left in service in 1905.