This is just a question and hypothetical.
If you scrap off the serial number on a gun, that is a crime by statute. If you scrap off the date on a 30-round magazine purchased outside of CO after July 1, there doesn't seem to a statute making that act a crime. Having a new 30-round magazine after July 1 is a crime, but the burden is on the prosecution to prove it. So, if you buy a Gen M2 or M3, there's pretty much no way the prosecution can prove it. It's another story if you buy a future Gen M4+.
Anybody disagree?