Mad Manor of Astabar - Moon Skulls

I'm DM'ing a run of Mad Manor of Astabar, which hinges on collecting 8x human skulls etched with the symbol of the 8x moon phases. I thought it'd be fun if my players could actually hold and examine the skulls, so designed the moon symbols & imprinted 'em into scaled-down versions of DanLuc's human skull.

References:
https://www.thingiverse.com/thing:224912
http://www.drivethrurpg.com/product/138937/The-Mad-Manor-of-Astabar