No, it is not a lunch box gun
, No, it is not a CIA gun
To restore it, AKA to return it to the condition in which it came from the factory when new, would cost a couple of thousand dollars To refinish it, which is what most people mean when they say restore, it would lose all collectors value. If it truly doesn't have a serial number, then yes it has been removed because it left the factory with one. The BATFE takes a very dim view of illegal firearms ( which with no serial number , that is what it is ), in easy terms, the 1934 Gun control act states the the possessor is deemed to be the one who committed the crime. Now I think the ATF has better things to do than pursue any action, but you never know, if you became wrapped up in another matter? It might be a good ideal to have a knowledgeable person to inspect it to ascertain the fact.