I'd think that 10700605101231
is the latest firmware - the "1070" means it's the 1070 (rather than the 970), the "060510" means it's from May 10, 2006 (the previous latest firmware is 060209), and the "1231" I think is just a time stamp for when it was compiled (shortly after noon).
EDIT: I edited my post to ask if anybody who has installed the new firmware could confirm the version number reported by their unit, and as I was typing it Scott posted.