Today after a scheduled oil change I figured I would change out the oil filler tube gasket because since I've had this Mattituck engine on the aircraft, there has always been a small amount of oil leaking from the base of the tube. Removed the safety wire and tube only to find that no gasket was ever installed. It looks like there's some thread sealant on the tube threads but that was it. Installed a tube gasket and safety wired back in place. Just curious, is it common to not have a gasket on the base of the dipstick tube on a new motor?