I'm not sure if there would be any potential damage to the dormant board, but I thought I'd offer a few possible solutions.
1. Wire in the diodes to your kick harness.
2. Wire your kick harness through a manual A-B box (VGA/Serial, etc) and mount it inside your coin door.
Obviously, not ideal solutions, but they may work well enough to get your money's worth out of the 2n1 you already bought.
-Stobe