These are real Kuhlii Pipistrelle bat (Pipistrellus kuhlii) skulls!
These specimens measure ~.5" long and are available worldwide!
They are sustainably hunted by the local peoples as a source of food and income. These bats have been studied and rated a level of "Least Concern" on the IUCN index of endangered/at-risk species due to their reproductive rate and widespread distribution.
These were exported with permits from the government of Indonesia.