I think they mean that it was a weapon of the same type, because the one used in Munich 2016 was an illegally reactivated prop gun without serial numbers. No way this guy could have now bought it legally.
Also, I don't see how guns from the evidence locker would get back into circulation. They stay there for ages and usually get destroyed.
Also, I don't see how guns from the evidence locker would get back into circulation. They stay there for ages and usually get destroyed.