Graphiccelerator comes with a ROM dump util called ATI Multi Dumper, ATIccelerator uses another way to tweak the graphics without dumping the ROM it seems.

ATI Multi Dumper 8.7 (PowerPC only): OS X and 9. Dumps the ROM of ATI cards, as well as a text file containing various pieces of information you probably don't need. Note that on-motherboard graphics cards (iMacs, eMacs, PowerBooks, iBooks) are not supported by the dumper tool. Does not support Intel-based Macs.

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Still System Profile reports some video ROM:

http://www.multiupload.com/POFRDV3OOU

After all, I dont think there will be an easy way to have something saved and I doubt you could use it for your G3 card. :-(