A bit of practical info about taking things to court.... from a retired cop who spent more than a bit of time as a courtroom observer -usually while waiting to provide a few moments of testimony if (and that's an understatement..) the matter ever came to trial....
Every day across the nation young prosecutors with a stack of cases they want to proceed with are literally strong armed by judges who point out that if they bring every case to trial - nothing will ever get done... The next item is to point out that there are probably a few cases that really are important that the young prosecutor is holding (and actually have solid evidence) so that's when everything remaining works its way through the system as a negotiation... At least that's what I observed down here in paradise, south Florida, over a 22 year span. I doubt that civil actions fare much better (except that every lawyer on every side - earns a good living while both sides get poorer...).
I actually did see "justice" once or twice in all those years.. It was purely incidental to everything else that was going on... This may sound a bit cynical - but it's what I learned to expect over the years.
In the matter of fake parts for carbines - proving the item is a fake won't be easy since there isn't a recognized standard to compare to (just a bunch of very well educated collectors who in the end will lack hard proof that the item involved is a fake....). If and when you establish that a particular part (or parts) aren't what they're claimed to be - how do you go about proving in court that the seller knowingly sold something that wasn't kosher? And of course if backed into a corner, maybe, just maybe our bad actor will, in the end offer to "make it right" but without any criminal action against him (or her) and the civil action might still proceed - if you can afford it...
I'm long retired out of police work (this will be my 25th year in "retirement" although I never retired at all - just went back to fishing for a living...) and glad of it... Justice does occur and more often than not - but not exactly in the legal system that I saw... Of course there's more than one kind of "justice"...