That's correct. Rockwells do not have springs in the kingpins to keep it all preloaded.
As far as the tolerance, I am not quite sure, but they are supposed to be tight. I've seen some guys hammer them on (the new brass bushings) and the knuckle took a fair amount of effort to turn. As long as you can them with the new bushings, then I would say they aren't too tight.
That is how I did mine and I've had success so far, but then again, I haven't driven mine too far (yet, first outing is from Birmingham south to the coast) and haven't convinced anyone that my Yoat is worth "welderin'."
You have to buy new brass bushings to get them tight again, but sometimes with the new bushings, some material needs to be removed to get them to fit....