Nuts with nylon inserts

I have replaced the struts and upper control arms on my 2003 Crown Victoria. The Ford service manual says to discard the nuts that hold the control arm and the nut that fastens the bottom of the strut to the lower control arm. Are these nuts a dealer item? Or is there a less expensive place to buy them? Is reusing the nuts so bad?

Almost every nut and bolt is to be replaced according to the service manual(I wonder if they even do it at a dealer or just charge for it), as far as I have seen, nobody that does it themselves will replace them.
I have installed the rear control arms on a few cars and reused what the car came with and replaced the front shocks with the same bolts/nuts they came with.