In this particular case, it would be a no brainer. The gun was most likely manufactured in Connecticut if made by Colt and was sold where? However, I don't think they need to prove it was moved interstate in order for the law to apply. The Federal Government wrote that law and ATF enforces it. In reality, I don't think they'd be all that interested in one particular instance. However, I for one, wouldn't want to go through the hassle of hiring an attorney etc etc to defend myself or become a person of interest with them. Then of course there are laws that might have been violated at the state level not to mention the possibility of criminal fraud in misrepresenting it as something it is not. It's just too messy to try to play Clarence Darrow or Erin Brockovitch with. YMMV.