I was just swapping the 9 speed over on my Anthem to 10 speed...after checking the M785 XT levers are I Spec B and the M780 shifters are also I Spec B....
But no the brake levers don't have the hole that the little M2 black bolt goes in..
Black bolt on the right
[img] 
[/img]
Do I need the nut on the left in that pic?
Brake levers part no is BL-M785
Shifters part no is SL-M780-B
If the hole is'nt present they are not ispec B. I spec A levers will use the parts 1 & 2 from your picture (L>R), I Spec B will use 2,3 and 4. You should find that the part 1 slips into the bottom heavy 8 shaped hole from the back on an iSpec A lever nicely.
I've got everything apart from the part on the 1st left!
Anybody got any spare ones?
I had the same issue a couple of months back.
Ended up rummaging and finding a T nut with the right thread (M5?) and cutting/filing the flange square. Still in there now, nice and tight.
[img] 
[/img]
Email me your address ben@birdmtb.co.uk
Do you have some of the nuts on the left? I need two of them..if so how much do you want for them?
Email sent