Parts were dimpled for AN427-4 rivets. Some holes need to be countersunk for AN-427-4 rivets. Some holes, where nutplates need to be installed, were countersunk for AN427-3 rivets.
The inboard and outboard hinge assembles were riveted together.
Two holes in the inboard hinge assemblies needed to be countersunk for #10 countersunk screws. For those holes, the instructions say to drill those holes to #12 size but they need to be drilled to #10. Drilling to #12 creates holes that are too small for the #10 countersink pilot.
