As for the Skyraider thats a franken-plane and its skin is made up from different texture files so thats why there an't any voids.
Don't remember ever seeing a void for the SeaFury but I thought the guy made the skins for it either lost or didn't want to release his template and hence no void.
T-6 Texan again I don't think there is a void but there's a template some where.