Myself, I match/order the stripped combo using the same manufacture (lower and upper), then just order a kit minus stripped upper.
Note: if you order this way, you need to be tooled up since you will need to build the upper together yourself.
Now if you’re not tooled up, there is still hope for a couple of options. The first is if you want to go RRA, then Chris at eagle firearms can hook you up,
Or if you can find a Double Star stripped lower receiver, then J&T kits are the mate to this lower (read J&T and Double Star firearms = husband and wife companies).
www.eaglefirearms.netwww.jtdistributing.comwww.star15.comP.S. if anyone else knows of other combo ways to buy/build upper/lower matching manufactures combos, please let us know. Granted that CM produces a great deal of the receivers (to the suppliers spec’s), it's the selling suppliers that usually have the receivers anodized, and here is where you get different sheens and colors.