You know, I am actually also in the process of putting my T-21 together, and am kinda confused about the CRL also. I painted my stock and pistol grips with a wood wash, because, well, its wood. I have seen 2 different rear sights. The one in the CRL looks like a bit of old phone cord, while the 2nd looks like some kind of "half-moon" greeble.
Also, that cable running alongside of the barrel..... what happens to it on the other side?