Small update, thanks to materials kindly shared by Hood - some more (originally there was just one) Peruvian P-36's.
There is a number of 'black-looking' photograps P-36's, but I could find a discussion on one forum devoted to Peruvian aviation, where one - apparently competent and with access to some sources - user claimed that it was Non Specular Sea Blue, so I tried with it.
![[ img ]](https://www.dropbox.com/s/68f0lnlirn3i1lr/curtiss_75_p-36_hawk_per.png?raw=1)