Bolt? I will have to start with “Once upon a time” or “You are not going to believe this” etc., etc..
The bolt was not the only part that was “demilled”, anti-gun types had pistols and rifles demilled, some were cut, others were sheared, cut was good, sheared without support fractured, parts were sold for scrap. 45 ACP became 45 ACPs with long slides/barrels, M14s became M14s, Problem!, a proud owner of a M14 was at a firing range when someone came over and ask him about his rifle, during the conversation it was decided the serial number of the receiver was among receivers that were cut up as in destroyed, the shooter and proud owner was instructed he was going to be given time to strip all the parts from the receiver for future use but the receiver had to be returned to the Government for destruction.
The M14 rifle was built in such a manner as to prevent it from being shot in a full auto. There was nothing suspect about the safety of the rifle.