Any markings or writing on the cards could be useful in determining what function they serve.
I'd remove the cover from the case then leave the computer in a window or other area …
Just out of curiosity, what are you mainly using it for? I've just won a 2.0 GHz dual G5 on eBay that will replace my 700MHz eMac for graphics (and a bit of audio/video)... I'm ant…