That seems to come up on a regular basis with me. To date I have swerved everyone off on it. I am a mechanic and if you let people do it to you they will be beating down your door for free advise and repairs. I find that building firearms and gunsmithing in general is much the same. I put a lot of hours into the guns I build or refinish and I really do not want to spend that kind of time on someone else's stuff and have to be compromised by their schedule. Building, riveting, welding (if necc.), pressing, head spacing , bead blasting, parkerizing, painting, and working all of the bugs out. We all know it is a lot of work to get one of these kits and receivers back together and looking like it should. So long as you are willing to commit the amount of time and effort required to do it then I would simply adhere to what Jack said and make sure that all of your U.S. parts are in and where they should be and have a good time. Any way you do it I would definitely insist on them building upon a registered receiver and not a flat that you pressed in your garage. It can be done legally, but it is a gray area that could put you in the spot light with Johnny Law. I keep all of my stuff on the up and up but that does not mean that I want to bring that kind of scrutiny into my life, thank you very much. It could be your best friend in the whole entire world and when he realizes that he may have to miss his kids growing up while he sits in a federal pen or he gives you up as the guy who built/helped him build an AMD, he's going to give you up in a heart beat. So just be careful with it.