I am going to assume that by moving the panel lines I drew in on my build log a tad upwards that the other Plank is going to be straddling the center line.
correct ... they all appear to be about equal width, with a panel on the center line and three flanking.
Another detail difference on the very early Albatros D.Vs -- characterized by the big headrest and the
longitudinal fore-aft under nose planking-- is former #5 describes a complete oval (not cut off at the top, like later versions) with holes on either side for the MGs. not sure if it applies to 1187, but my guess is it would.
I'll be modeling all of this stuff -- fore-aft planking, early "big" headrest, alternate former #5 -- for Aircraft in Pixels, so stay tuned for pix. Info based on factory photos kindly supplied by Jim Miller.