You're creating a false equivalency. There were no requisite serial numbers. Everything they did was both within the letter and spirit of the law as written. This is like saying "Well, you bought a new iPhone with headphones. We here at BIG GOV REGULATOR approved iPhone and headphones, but not the iPhone WITH headphones! So enjoy prison!"
Again, there is underlying presumption here that I just don't agree with. The law itself is the violation of the right. But disregarding that, how does one "skirt" the law? It seems to me one is either obeying the law or not. For example, if I am in a 30 MPH speed limit zone, and I am going 29 MPH, am I 'skirting' the law?