I had asked about it, evidently 2 years ago:
https://pinside.com/pinball/forum/topic/where-to-get-bally-coil-31-o-55-bell-ringer
Has APB_Enterprises - or anyone else - gotten around to making a reproduction?
What about the sleeve? The total length is 2-1/16", with the ring at 3/8". The material is brass.