Do you mean the cap that tightens down on top of the spindle?
If so, then no!
, but its not very tight. The idea is to tighten it enough so the bearings are held in place, but not under much pressure.
I haven't got the Haynes book of lies to hand, but it is something along the lines of tighten it to a similar level as you would a spark plug, then actually release it by approx 1/4 of a turn. The end result should be a little bit tighter than hand tight?
Not very scientific I know, but the best I can do.