Pretty sure Genie used Shark Fins just like any other Gottlieb late model EM or System 1 - 3.
I was pretty sure that Atari used pegs. Here is an old thread that shows photos. It has pegs, but no fins (yours looks like the fins are for alignment only). The last post says the one pictured did not fit so there must be two styles for Atari (besides Hercules!).
https://pinside.com/pinball/forum/topic/wtb-atari-lockdown-bar-for-superman