I have tried calling the ATF field office in Toledo, OH to ask questions.....35 minutes would be about right for your hold time on the phone. Let alone a live agent going to a gun store and looking at a gun ?
I saw a guy carrying a Thompson around a Lima, OH gun show once that had a sub 16" barrel, people kept asking him if it was NFA, he was an older guy and he had no idea what they were talking about. They have a Deputy Sheriff to work security...he finally went over to the guy and told him "get that thing OUT of here, put it in your car"....turns out the guys son had asked him to sell it for him. I did not look at it real close because I had no desire to be involved in any way. I have seen older rifles like Stevens Favorites cut down into pistols for sale on peoples tables at gun shows. A buddy of mine bought one actually....on his way out people at other tables were screwing with him "you know that is a cut down rifle don't you ? That is illegal"...but he really did not care. Amazes me really. I go to great lengths to avoid stuff like that.
There IS a provision in the law that says if you turn in something illegal (sbr, mg, sbs, etc.) that you will not be prosecuted for having it.
Bill