If I'm understanding the topic correctly, its about the nuts that go onto the 8-32 norn bolt and tighten against the control surface. Right? If so, its not a mistake. They arent necessary, except on the rudder if using a bolt throught the rudder for pull/pull. Glue the bolt into the hardpoint in the surfaces and it wont go anywhere. The nuts wouldbe dead weigh, and as with building any model where weight is critical, weight savings comes in small pieces everywhere you can take it out.

I've never used jam nuts like that even on 40% models and am quite confident that ther arent needed on the ST4D.

m