The law is the law, but it is not always equally applied. A couple of years back an AK47 turned up for sale. There were no papers, but the finder was an attorney with a large firm. With a little help it was determined that it was probably a Vietnam bring-back, and had been registered during the 1968 amnesty. After being registered it had changed hands several times in the ensuing 45 years, but with no paperwork. With a little help the original registration was found, and the finder was able to get the AK registered in his name. Federal law was broken numerous times, but in the end a little help from your friends was all it took.