Killed me with the "smells like mushrooms" comment. Good move choosing to get this one back together instead of parting out. That playfield is great (FP's are often beat) and the boards do look clean, especially considering how that backbox looks. Repair shop should get them sorted out easily. You probably could have got it booting with some solder work on the header pins, but as others mentioned the sockets are likely toast. The work to replace them isn't exactly hard but if it's not your forte, an experienced hand taking care of that stuff for you is a step in the right direction.
Richard