This is not correct sir.
I have seen the rules pertaining to this and it is 100% legal for me to do this machining myself or to hire someone to do it for me, so long as it is machined for a semi auto configuration and not full auto. I know what must be done, but don't have the equipment to do it.
What I have now is what is known as an 80% receiver. It is now for all legal purposes just a hunk pf metal but when the machine work is finished it is then considered a firearm. This same principle applies to literally a hundred thousand other 80% receivers sold in the USA annually. None of them are considered guns but when a few more holes are drilled they become firearms, per BATFE rules.
In my case, the Kit must be machined also to allow for only semi auto use which I will have done. The Right Side Plate is drilled and a minor amount of machining is done and when assembled I will have a 100% semi auto, 100% legal firearm.
If you wish to dispute this, I think I can find the necessary legal documents that allow for this.