Got my 6 Gigabytes today!
How do I know whether they are f60 or f70?
Download atiflash and have it read your current BIOS info. You can also use the Gigabyte @BIOS utility if you're in Windows, but I'd recommend using the DOS ATIFLASH utility to flash the new BIOS.
Yes, ONLY use the BIOS I linked to earlier if your cards have the F60 BIOS. If you have the F70, you're all set. They are not compatible with each other, and can't be swapped. Meaning you can't use a F70 BIOS on a F60 card, of vice versa.