7A fuel tank question

On page 7-5 of the wing kit instructions, under ?Fitting the attach angles...?, it says we should ?Remove the angles [T-712] and drill & rivet the nutplates to them...?. This sounds like the nutplates should be riveted to the attach angles. However, DWG 16A, detail A? looks like the nutplates are attached on the aft side of front spar W-706A-L. Should the nutplates be riveted to the attach angles or the spar?

The most inboard Z bracket has 3 holes for bolts to go back through the spar & nutplates there.
The other 6 Z brackets should have nutplates to receive bolts that come forward thru the spar.

That makes sense. Thx much!