I am considering building a preban M4gery using a Colt 6920 upper and with a Colt preban lower. The blue label Colts seem to have a darker Colt grey than the green label Colt prebans, did Colt change the finish color? I realize neither blue or green labels will match exactly the black matte finish of the new Colts, but I would like to get as close as possible. Also did they vary the finish among different models such as blue label HBARs and blue Gov't Carbines?

Coming from an enormous Colt fan, I gotta say that getting a close upper/lower color match from a factory Colt is hit or miss, therefore, if you're going to mount a new 6920 upper, you'd be best served using a later P.B. blue label lower to get as close as possible to matching.  Good luck.

Sometimes you just get lucky.
I got a Colt Large hole A2 upper on EE.
It matched my SP-1 better than the original SP-1 upper.
[img]http://www.digitalpose.com/mbr/1/20296/p/320298_374245835040538525_vl.jpg[/img]