I have a four digit receiver that I built into a rifle. Has some gas trap parts and some 1945 parts, and a lot in between. I had a nice SGM stock and type II lock bar sights. It's just a fun to put together mix. What is special about it, a 6 thousand SN receiver, is that it was stamped almost on my birth date in December 1938. I don't think I'll be selling it very soon.