I have not owned a glock for some time. A local dealer had a couple custom finishes that they stated were factory, but I cannot find any information on the finishes on the glock website. I purchased a burnt bronze version with slide and frame in burnt bronze. They only had it in a G19. They also had a Light desert sand and full grey on a few other models. Anyone have any information on these? Any idea why the backstraps are in plain black?