Perfect 360s are stupidly rare in both the Wico and later Happ variety. I don't think they ever came on any machine, they only existed as an expensive upgrade that almost no ops would ever shell out the money for. They were around $100 when Happ stopped selling them.
I have the Happ ones on my cabinet with Robotron handles on them and they are incredible.
Also, people want them to do Berzerk restorations, as they reproed the optical stick handles to match up with 360 hardware no realizing when they did it that the 360 bases were almost as rare as the original Berzerk optical sticks.