I think it is only justice to acknowledge that the creator of the Fidelity Serial Number Theory was Yovan, also known as yoyo_chessboard, as can be seen in the Hiarcs forum thread which has precisely that title: YoYo's Fidelity Serial Number Theory.
https://www.hiarcs.net/forums/viewto...215d61b97f0757
Yovan also collaborated with MAME in the emulation of Fidelity machines.
Unfortunately Yovan passed away a few years ago.
Saludos,
Luis