Should not bother your RAID setup.
After updated though, you will probably have to reset your BIOS options for Boot order, boot from RAID, etc.
WORD OF ADVICE HERE....
When it comes to updating your BIOS, the best thing to keep saying over and over and over to yourself is "if it ain't broke, don't fix it"
Unless you need to update to fix a problem, and the update says it specifically WILL fix your problem, leave your BIOS alone.
Updating will do absolutely nothing for you. And if you mess up you now are the proud owner of a completely dead motherboard.