These are caged nuts and i think that they can be found at http://www.mcmaster.com
. I did pick up some of the square and caged nuts for the dashboard a while back. I do use anti seize on everything that i assemble now.
Do a search at mcmaster carr for "cage nuts" if anyone wants to get new ones. I do try to keep it all orginal were i can but i feel your pain too. My welded nuts in the frame are gone from the PO he broke them i guess.
BTW: On my japanese car i have problems with the spark plugs taking them out. I heard the metric threads on the bosch sparkplugs aren't the correct size. I just had problems again removing them. Now the autolite plugs are in it with anti-seize(moly) now if it lasts another 50k we will see if it has the same problem again but its at 195k now. I think the cad plating on the bosch plugs doesn't like the alumimum heads. They go in easy but come out really hard.