From the article cited above:
we were joined by Republican and Democratic mayors saying we need to do something about ghost guns. They?re untraceable. Often, it?s just clicking two or three things together ? they come in the mail ? assembling the gun, no serial number, not conforming with any of our standards or background checks, and we need to take action on that,? Polis said.
Wow.. Apparently just like legos... No skill or tools required I guess... Snap two or three pieces together and BAM, fully functional and reliable... Where can a guy get some of THAT? ...asking for several friends...