Hi Mike,
Interesting point! I had a look through the posted pictures again – although I haven’t had a chance yet to look through all pictures. It appears that the mandibular unguis seen from the right looks paler than seen from the left. If you look at the shape of the gray/white border at the neck, there is a slight irregularity on the right side seen on most pictures (from the right) but #9889 and #0003 (in both cases the angle makes it difficult to impossible to see that particular area). On the left side there is a very conspicuous pattern with a line diverging from the left laterodorsal base of the hood towards the chest. This is seen on all pictures where the angle makes it possible to judge.
Therefore I believe that it is only one bird and that the difference seen in the mandibular unguis is a combination of as asymmetry (R
