They can be key restore/revived yes, I believe the Inifinikey also works with the all-in-one board layout (but prob check with @undamned first).
You can even convert these all-in-one boards to other CPS2 games IF you have a Darksoft CPS3 system/cart (it can write that SIMM with the game data).
And as recently discussed in another thread... You can also sack/harvest the A-board custom from these to repair a dead CPS1 (a pretty good use for these if you ask me, as installing the multi kit will never be an option).