These are real brown pipistrelle bat skulls (Hypsugo imbricatus - formerly Pipistrellus imbricatus) ! These bats are found throughout Malaysia and Indonesia.
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 high reproductive rate and widespread distribution.
These skulls are roughly .5" long, and can be shipped worldwide!