I have the dataset

dataset=Dataset[{
  <|"x" -> 320, "y" -> 178, "z" -> 291|>,
  <|"x" -> 360, "y" -> 114, "z" -> 109|>,
  <|"x" -> 400, "y" -> 186, "z" -> 265|>,
  <|"x" -> 440, "y" -> 419, "z" -> 469|>,
  <|"x" -> 480, "y" -> 228, "z" -> 251|>,
  <|"x" -> 520, "y" -> 153, "z" -> 129|>,
  <|"x" -> 560, "y" -> 284, "z" -> 177|>,
  <|"x" -> 600, "y" -> 246, "z" -> 323|>,
  <|"x" -> 640, "y" -> 333, "z" -> 108|>,
  <|"x" -> 680, "y" -> 383, "z" -> 261|>
  }]

I want to change the "z" values to 0 if the corresponding "x" value is smaller than 380 OR larger than 620.

If this dataset is a list, I can do

data = dataset // Values // Normal
Map[
 If[#[[1]] < 380 || #[[1]] > 620, {#[[1]], #[[2]], 0}, #] &
 , data
 ]
% // TableForm

But I need some help achieving it when the numbers are inside a dataset.