I don't know which government agency would be responsible for that. What is realistic depends on the type of weapon. If they are parts for small arms, there's very little that you can do necessarily. If they're Javelin missiles, if you follow the U.S. lead, for example, with Stinger missiles, the shoulder-fired, surface-to-air missile, they do 100% physical inventory by serial number of every single exported missile ever. They do that annually.
On October 18th, 2017. See this statement in context.