Yup, back around the 60's the DCM sold 1911's through the NRA. NRA membership used to be required to purchase, IIRC.
M16's, even if converted to semi, would still be machine guns in the eyes of the BATF. The lower receiver and trigger group would have to be replace with semi parts. Could an executive order fix that prob, I don't know.
But in any case, memory tells me that the CMP charter only allows them to sell .30 caliber rifles and the .22 rimfires. So, no .223, no .45, and some say, even if you could get the m14's converted to semi-auto, and past the "once a machine gun, always a machine gun", they still could not be sold unless the CMP charter was updated to include 7.62mm rifles. Yes, I know that .30 and 7.62 are the same diameter, but the m14's are chambered in 7.62 NATO, and are not .30 caliber.