Quite the perceptive one 
. Yes, that’s same white paint that I used on my Bottlehead Crack:
This is the Open Alpha design with a slight change to accept dual 3.5mm instead of the dual Hirose connectors (I’m not buying another cable if I don’t need to).
Details here: https://www.head-fi.org/threads/open-alpha-t50-3d-printed-headphone-project-from-mrspeakers.825868/
3.5mm version: https://www.thingiverse.com/thing:4250218