There are no transferable Glock 18's in existence. The G18 was made after 1986 so it isn't fully transferable. It is also not made in the US so it is bound by the GCA of 1968 which banned the importation of machine guns for civilian ownership. This allows SOTs to possess them but no individual can have them as they would be in violation of the GCA 1968. There are no pre 86 dealer samples, again because it was designed and made after May 19, 1986.
I seriously doubt there are any registered auto sears or the like in existence that are fully transferable. The concept of the full auto Glock wasn't made public until the release of the G18 in 1986. I doubt anyone designed, made, and registered any conversion parts for the Glock 17 before May 19, 1986.