sir, thank you for reaching out to me, im a long time reising collector,,actually these are quit scarce guns,onl something like 3500 ever made, i have been collecting data on them for 20 years,,id like what number the change between blued ,finn barrel and parkerize smooth barrel occured, so does your gun have blue and finn bbl or park andsmooth bbl, and is lug cut for auto connector , and SN,, let me know,,i have quite a list of sn,s that i heard about, ive reached out tosome writers but never got a reply,,,the m60s are interesting as they have always been under the radar and never on any ban list, i dont leep any names just the feature data,lets hear from you, welcome to the board ! best billy dixon