I'm trying to troubleshoot a constantly clicking relay K1 on a BSD (same WPC hardware as HS2, I believe), so I was looking at the schematics of the driver board. It looks like J109, J110, K1 and a handful of other components are there to power flippers, but since these games use the Fliptronic II system, this circuitry (and J109 and J110) are not needed. So I don't think it matters (at least for HS2) whether or not those components and connectors are populated...