I double checked with Tier-2 and they told me it was.
Look at the build date, Tim. Firmware Build Time: Sep 2 2010 16:28:51
, which is the one LarryHolmes posted, vs the one I posted - Firmware Build Time: Jan 26 2011 13:53:12
Now, if there's a reason they've gone back to a older version that I don't know about, maybe you can ask your source in Tier-2 to tell us why.
I will say some users can use factory firmware and have good results. Some however need the update.