We occasionally have them, none now though. Pretty sure that the ones for Cougar and Maybe Lincoln/Thunderbird may have taller posts, due to the thicker seat foam?
Majority of them have split at the base of the threads, or broken somewhere in the middle, either during installation or just time.
They could be dummied up by using the chromed seat latch bezels glued to the top of PCV pipe. It would fool most casual observers.