Here are three different variants of Colt Flat Dark Earth (FDE) in my reference collection.
Attached FileTop example is a cerakote carbine upper receiver from around 2017.
Middle example is an anodized LE6940 upper receiver from a limited production run of about 1500 examples. Estimated time frame is 2011/2013. Note the bronze tone in the color.
Bottom example is an anodized prototype IAR6940 upper receiver from around 2008/2009 time frame.
I would like to say a special "Thank You" to a member here that made owning the IAR6940 upper receiver possible.