Last year I bought a pre ban lower receiver from a man in washington, before buying it I checked the ser #s with bushmaster and found out it didnt leave the factory as a complete weapon. The seller told me that he knew that the original owner and that it was made into a complete weapon before the ban and he would get me a notorized letter saying such. I made the mistake of buying the lower and taking his word that the letter "was in the mail" due to a computer problem I lost his address and phone #. My question is this do you know a way to find out who the original owner was through the serial # on the lower or any other way I can settle this once and for all . thanks.