KS, your correct the ATF doesn't know exactly what's out there.
Some people hoped for another amisty so the ATF could start their regestry over but I don't think they'll ever do that agin. The pre guns I talked about were pre 86 Dealer samples, dealers are allowed to keep them if they give up their FFL most all the rest are sear guns. Here in MO. a lot of people use a C&R to own title ll weapons because we have to have some type of federal license to obtain any of the good stuff. Your lucky where that's concerned. Missouri is kind of funny about title ll stuff, we can own MG's and AOW's but no superssors unless you are a class ll mfg I could never figure that one out. I don't know all there is to know about the subject but am always willing to listen and learn.
You seem to pretty well versed on the subject, have you ever been to Knob Creek? It's a hoot.