You sure are paranoid.
Do you own any silencer's?
I do,I have 4 of them that I did with a Form 4 Trust years ago. I'm also in the process of doing three Form 1 builds from Solvent trap kits. Went to the Sheriff's Dept. today to get fingerprinted,but the person that does them is on vacation this week.
On a Solvent trap,as long as the end cap isn't drilled,it can't be considered as a silencer/suppressor because you can't actually fire a live round through it. The ATF might not like it,but unless it is drilled completely,it's not a silencer.
Think of it as an 80% lower,it's not a firearm until you machine out the trigger area,and the holes for the trigger pins and safety.
It's hard for them to say it "Illegal Constructive Intent" when you have an account on the BATFE website,have done or have attempted to get fingerprint cards,and have arranged the services of an engraver to legally mark said items once you get approved for them.