This kind of thing already happens in established fields of forensics all time and if they couch everything in enough authoritative sounding language nobody who doesn’t already know a whole bunch about the topic is going to be able to call them out on it.
Bingo, the goal is not to actually trace 3d printed guns, it’s to add another piece of evidence they can slap onto the target of their investigation to improve the chance of getting a conviction. Whether the accused is actually guilty of anything is truly irrelevant to the intended purpose of these kind of things, they are in practice assumed guilty by the prosecution unless proven innocent. The point is simply to make a convincing case to a judge or jury.
Bingo, the goal is not to actually trace 3d printed guns, it’s to add another piece of evidence they can slap onto the target of their investigation to improve the chance of getting a conviction. Whether the accused is actually guilty of anything is truly irrelevant to the intended purpose of these kind of things, they are in practice assumed guilty by the prosecution unless proven innocent. The point is simply to make a convincing case to a judge or jury.