I was curious about the QR codes that Colt uses on it's newer products so I downloaded a QR code reader app on my phone and found this......

Inside the box QR Code:   #AR6951@$LTA015200$%12072016%#          Contains Model #, Serial # followed by a date with a format MMDDYYYY and is dated BEFORE the end box date.
End of box QR Code:        #@AR6951@$LTA015200$%09122016%#       Contains the Model #, Serial # followed by a date with a format DDMMYYYY and is dated AFTER the inside box date.
Receiver QR Code:           D13629LTA015200                                         Contains the Colt CAGE Code 13629 and the Serial #.

Colt says the carbine was made in July/2016 and the barrel is date stamped 10/16 so I'm not sure about the other dates on the box?

It's possible that the lower was serialized before the build date, pretty sure one the lower is completed ATF wants a serial number on it...

My AR6720 has no code on the gun, yet has a code decal inside the box and the typical end of box decal.  The dates are 14122013 and 12132013.  The bag is dated June 2013 and the bbl is 02/13.  Very interesting.

OK it makes sense once the lower is completed Colt considers that the manufactured date.
Perhaps the inside sticker on the box might be when it was packaged and the outside box sticker when it was shipped.