I have the same board and no drivers are required nor should be used for RAID when installing Windows 7. Windows 7 has the RAID drivers natively.
I don't know about your board but I have a GA-x48-DS5 and there are no pre-install drivers available for raid for my board at gigabyte.
There is however a post install driver for raid (motherboard driver sata gb sata2 raid) They provide them, I use them, as gigabyte should know their own hardware I can only assume they are needed/advised.