I have a Power Mac 6100 that had a similar battery detonation before I got it. I cleaned it all up very carefully and it works fine. You can most likely get that board to work again with some fiddling and testing, maybe a couple of wires here and there to reconnect any traces that are eaten through. I also have two Mac IIs and a IIfx that had similar problems. The IIs were resurrected as well. The IIfx remains damaged in the power area and I still have to jump-start the power supply.

Those things are crazy, I have since removed all batteries from my Macs. I'd rather go without PRAM settings than risk it.