You can find all the PRO-CT0 protection check at here, however it is easy for just patch to put the result directly and pass the secure check.
https://wiki.neogeodev.org/index.php/Fatal_Fury_2
This one confirmed can two to two replace, can’t just replace one because the height is little bit different.
https://e.tb.cn/h.83FtBWJfuomIZ7X?tk=FhT9gvSPuPM CA381